True, but fee is also what prevents btc from become a payment option in a small shop.
If you can’t pay 500 sat for gum, without paying an additional 5000 sat for fee, it’s never going to work.
As I understand it fee is not really a requirement in btc, but a necessary evil in order to get your transaction included (timely). Of course once the block reward stops, it’s the only incentive for miners to keep producing blocks, which carries your transaction. Ironically this is what prevents btc from replacing other payments methods in minor daily usage.
Well as I said, it is there mainly to stop spam. The fact that the payment to miners will be in fees is I believe just killing two birds with one stone. The block reward could have been implemented to go on for billions of years and the mining fees could have been replaced with a small proof of work attached to the transaction, but since proof of work is already done by miners and burning coins as a mining fee would have a same effect as just having mining fees without the block reward. You might want to look into the Lightning Network, it was designed to solve these problems.