The simple reason why so many people love Bitcoin is because of its decentralized nature, because the coin is based on proof of work and the possibility of getting profit from the coin during bull season. Most people are investing into Bitcoin because of the profit that it generates to them and as long as Bitcoin is going main stream and demand is increasing, people will continue to invest.
but yes, the point is that btc is a valuable asset because the amount is small, which is only 21,000,000, so it is appropriate that btc will be a good coin because for this simple reason, of course people will see that btc is a good asset.
Bitcoin is not a valuable asset because the total max supply is just 21 million, that's so wrong, there are alternate digital currencies in this space with 10 million and 5 million max supply and yet they can't do what Bitcoin did, it's not about max supply.
People don't get how big the decentralised in nature of Bitcoin really is, the only thing that comes this close to me is the battle with inflation, it just seem to be the best thing to tackle inflation and I bet that's why every institution want some Bitcoin now, they slept on it for years and now they've woken up.
Now that people are just realising how Big Bitcoin can be, they are moving so fast to buy everything that they can, to me Bitcoin is also a good store of value, I will rather have a lot of money in Bitcoin and have small amount of Fiat in my bank account, mainly for food and bills.