Perhaps one factor that affects a country forbidding bitcoin is that a country does not impose a tax on bitcoin, so there is no additional income to the country. Hopefully the future in all countries can legalize bitcoin.

I don't think the banning of the cryptocurrencies would be more effective and the best option i think we should be applying is that we better make some ways to manage those crypto coins because crypto coins cannot be banned suddenly and also banning cannot give you ways to stop the bitcoin trading in your country. For complete ban, you need to stop the internet around your country which is not possible and so you better make some way to manage them with tighter security.

many influences from chinese countries but many countries support bitcoin investments :
Japan
Japan in April 2017 began receiving Bitcoin as the legal currency. Then the electronic retail giant, Bic Camera accepts payments using Bitcoin one week after the cryptocurrency is passed.

Quoting CNBC, Bitcoin's trading using the Japanese yen is the second most liquid after the United States dollar (US). It was mentioned by a trading platform of Gatecoin cryptocurrency.

"The act of legalizing the Virtual Currency in Japan has the potential to have a big impact, because there have been many rumors about Bitcoin's endorsement," Gatecoin Founder and CEO Aurélien Menant said as quoted by CNBC, Friday (8/9/2017).

United States of America
The US is the number of countries that use the highest cryptocurrency in the world. Citing bitcoin.com is reflected in the high trading volume of Bitcoin.

The high volume of trading occurs due to the support of Silicon Valley which is home to thousands of start-up [Suspicious link removed]panies. The US also has the largest number of Bitcoin ATM machines in the world. The country has always been a leader in digital money.

Denmark
Not only become the most technologically advanced country. Denmark is also the most vigorous country in encouraging the elimination of cash and using digital currency.

Although friendly against the use of Bitcoin, the Danish financial authorities belim recognize Bitcoin as the official currency. But Bitcoin remains usable, because Denmark is home to a number of cryptocurrencies.

South Korea
South Korea today can be regarded as the world's largest technology producers call it very famous products such as Samsung and LG.

The country has the highest smartphone penetration and mobile payment rates in the world, not surprisingly South Korea is rapidly embracing Bitcoin as both an investment and payments or money changers.

Citing bitcoin.com, Bitcoin services are considered safe by using Korbit. In South Korea, people can also buy Bitcoin at 7-Eleven outlets all over Korael.

The country has also hosted a regular Bitcoin conference and has created a friendly climate for the Bitcoin user community.

Finland
Like its neighbor Scandinavia, Finland is also one of the leading countries in terms of technology. The country has also exempted taxes for the purchase of Bitcoin.

Finland already has a very large number of ATMs to meet the needs of the country. From the coinATMradar this country is the most Bitcoin exchange place.

In January 2016, Bitcoin was used to buy a Tesla S series car for € 140,000.

In my own opinion, many country whose government are banning bitcoin or even all cryptocurrencies because they are against it, the government can't earn from people who are earning in bitcoin because bitcoin has no tax.

 Most governments consider Btc a threat to their economic growth,  the independence of BTC from regulatory institutions means that it cant be taxed, thus denying most government income tax returns

This could be as a result of the fact that At the moment, governments of all countries are not able to track transactions made with the help of crypto currency. Hence, there are other reasons. Mining requires a lot of energy, at the same time, there is no legislative base that regulates energy consumption, taxation. And, of course, this is an excellent opportunity for terrorists and scammers to commit their dirty deeds, which is unacceptable.

Government as it were are a set of body putting the affairs of a country under their control. The major reason why the ain't happy with the Bitcoin is because it can't be controlled; decentralized. Hence the government ban on Bitcoin as they dont have control over it and it is somewhat making the citizens to be at liberty without the government's interference.

Ada kemungkinan kepemerintahan melarang bitcoint,karna pemerintah mengganggap bitcoint itu akan menghancurkan masa depan warganya

Because they can use for illegal activities that is anonymity of transactions makes Bitcoin a good ally of criminals and could be used for drug trafficking, prostitution, terrorism, money laundering, tax evasion and other illegal and activities.

The basic summary of governments banning bitcoin is to guard against its citizens from being swindled. Also, because the government doesn't have a full control of the Bitcoin/Cryptocurrency system yet. From my view of what my country's government hold is that they are not fully aware of its full potential, hence they are not that decisive of a ban or not.