probably because of congestion and traffic overload. It is bitcoin season and even people who know little about crypto will come in to buy and this might be the reason. coinbase will make alot of money from fee so I do not see reason why they will intentionally do this. Even the CZ binance also make mention about getting binance server prepared when a whale alert was received. you can check his twitter handle for this.

Be careful. This may be fake coinbase sate you login.

I find it interesting that the couple exchanges I'm close with have presented a huge influx of new users. Compared to last month at least, seems that these last couple of days people have been registering en masse. It's possible coinbase saw a similar behavior and wasn't prepared for it, heck, it's funny to type that out. "Coinbase wasnt prepared for it"

Coin base has 5.6 million users , in January 2018 it had 11.1 million users .
Now the site is incapable of handling high amount of users at once. One needs to understand that at times like this where one can expect high amount of traffic the website needs to be upgraded to support it . Plus everyone knew halving is a historic event and therefore it should have been done before.
The downtime on the websites does cost them themselves therefore making it even worse for most websites , so if coin base would do this on purpose the chances are they are loosing a good amount of money too.
But if they were paid correctly by some big whale to do that then the chances are they did not upgrade their website and what they were paid was Preety big amount.
See it is a decentralized network but still it does not stop people from playing dirty.
But at the same time I do doubt that coinbase would actually repeat their mistakes again and again . After 2018 they should have already upgraded the site plus prevented the clustering of users so that they can all use the website efficiently.
I think my take on it would be :
They are doing it on purpose.
But then again what they are doing is not against any rules. Therefore there cannot be any action taken against them , even if people go to the court they would be advised to just leave and use another exchange.

Coinbase exchanges don't do this on purpose, because it is not profitable for coinbase to do so. The existing coinbase reputation can be bad
if they do that, in my opinion this is just a technical problem. Coinbase should upgrade their system immediately. If the system is not fixed
immediately, the coinbase can be left by its users. Because now many exchanges that offer good service and of course with a good system
as well, so make users comfortable.

Mainwhile I've checked coinbase and right now it seems everything is fine. Running good. I have been using coinbase since 5 years. I notice not only coinbase but also others exchanges crashe when there is a big increase or decrease of bitcoin price. Maybe because of their hosting unable to control a lots of traffic during that incidents. So don't think coinbase has done this outages on purpose

I also noticed that coinbase during the dumps and pumps crashed the system, initially I thought it was done on purpose by coinbase itself, but in my opinion btc every day finds new investors and with the increase of users who place orders during the pumps or dump leads to a blockage of the system APIs. personal opinion of course

I don't think this issue is only about Coinbase. All major exchanges, including Binance, experience similar problems after the frequency of orders entered and canceled during sudden price movements.

But they should have already find the solution for this problem as it was not the first time to happen. When it first happened, they should have identified the solution or were they confident about their system? If it will happen again in the future, I don't think it will be good on their image.