1) Slow transactions
you have obviously never used bitcoin in your life before.
or possibly you are trolling us.
bitcoin transactions are instant. the confirmation of these transactions are also fast enough. for all bitcoin's history it has always been 10 minutes on average and will continue to be.
2) No reimbursements
i suggest reading the white paper.
it is designed this way to solve the biggest issue that the other payment systems pose. the issue of charge back scams, the issue of each business needing a lot of registration, a lot of verification and information just to let you make a payment with old systems.
with no charge back, the business can trust you, and you trust the business because of its history. like when purchasing a game from Valve (Steam).
If I make mistakes in sending bitcoin (and people make mistakes all the time) I wont never get reimbursed in any way
its not the same with FIAT.
no, people don't make mistakes that easily. you actually have to try so hard to make a mistake in bitcoin because bitcoin addresses are not easy to change. if you change a letter it will simply become invalid.
that is why i repeat that you have never used bitcoin in your life before!
If someone clones my credit card I have some chances to get my money back
what about bitcoin?!
then use credit cards if that is what you like. nobody is forcing you to use bitcoin!:D
Moreover, some more modern currencies have a better technology.
If we really will use cryptocurrencies in daily life, why should Bitcoin be the best coin to use?
because it has been the best so far.
other cryptocurrencies (aka altcoins) are good too, but they have flaws. many flaws in some cases that prevents them from even achieving something real. at least it has been like this so far but it does not mean it can not change in the future.