BUT if BTC cannot serve as storage of wealth for all and neither as day to day currency due to very slow and increasingly expensive transfers, what role will BTC play in the future?
Probably it's for a investment, just like gold.
I understand the current fees is quite high, so it's not recommended to transfer/spend little amount Bitcoin. But we can't know the future, does Lightning network will be used worldwide next? It will solve the high fees problem.
I honestly think that it will become a billionaire's toy in the future and coins like XLM which offer incredibly fast and inexpensive transfers, will play the major role in the financial day to day transactions.
So I believe that the people who have just started to invest in crypto should consider these other coins and forget about bitcoin.
People can choose what they want to invest/buy, but Bitcoin as a mother of cryptocurrencies can't be forget. It's the first crypto that ever exist and already reach top 6 on total market capitalization of all company in this world.
If the world will accept crypto as currency, it won't be BTC.
Read
https://www.opennode.com/blog/bitcoin-regulation-which-countries-are-bitcoin-friendly/