After the world sees the latest bitcoin, the algorithm of the network will not change because of this - new blocks will continue to be created further.
Since the release of new coins will cease, the miners' remuneration will consist of commissions that network users pay to add transactions to the blocks.
The termination of the issue of bitcoin will only increase the price of the coin, so far it is not a question of how useful it will be. Bitcoin is digital gold, gold of the future.