I learnt that Bitcoins and some other coins use POW, so they have transaction and mining on a same line.
That means, if all BitCoin blocks are mined in several years, does BitCoin lose its usage as transaction?
Is that right?
Also can anyone recommend me a good site where I can learn about types of cryptocurrency proofs?
There will always be more blocks to mine, only thing that happens every 4 years is that inflation of bitcoins halves eventually approaching zero.
Miners will always be able to earn transaction fees from transactions they include in their blocks.