There is a definite supply of bitcoin. Bitcoin will no longer grow when the whole bitcoin mine is over. So there is no fear of inflation here where there is fear of money inflation in every country. So everyone is interested in Bitcoin and everyone is buying Bitcoin as a valuable asset like gold. So Bitcoin is gaining popularity day by day and its value is increasing. that's why bitcoin is valuable
The idea of bitcoin being finite is not the real reason why we care about the price of it. The real reason why we think it worths something is the fact that nobody controls it. USD or Euro or anything else could become less valuable due to inflation all because there are people at the top who make it so. But, bitcoin is not touched by anyone or controlled by anyone and that is why we care about it so much.
I would rather lose all my money in bitcoin, then keep it in dollar and have it slowly become less valuable. Any investment made in fiat would be racing towards inflation and hoped that it wouldn't be this low, and that's why there is crypto, it's the main reason why it was created.