I really liked the arguments in you post and agree with all of them.

Bitcoin was intended to be an easy to use, unregulated and cheap payment system, but it really sucks as such. There are many cryptocurrencies that work way better for payments.

But the variety is also the biggest downside, because it is hard to put trust and money in one coin when there could be a new, better one coming up every day.

Bitcoin is different. It is really bad for paying, but because it is so widely known, it works great as a store of value. When there is true mainstream adoption of blockchain systems (several million daily users) this might change, but this is how it is right now.