I've always had the feeling that a lot of smaller bitcoin owners are speculators who bought it with cash they're probably going to need in a month or two, and I think that's especially true during extended bull markets.
This is not bad at all so far the fiat is used for something than holding it in bank. There are even non-crypto related works that are profitable, some people can think of selling some of their bitcoin holding for such reason, some will even sell some for other crypto and non-crypto benefits and opportunities.
When you sell, is no longer yours. When you sell your bitcoin for more than you paid, you may be happy about it, but unless you have an investment to make or would like to buy something else, all you have left is... fiat. And fiat finds its way out of pockets very quickly.
It is even better in developed countries like Europe and US, the fiat devaluation in developing countries and underdeveloped countries is much more while the developed countries fiat currencies are still centrally controlled and devalued.
The present bank app I am using have a very friendly GUI that even new users can be able to see 'save' which is just like fix deposit account. Some people can be encouraged with the profit, but the rate my country fiat has been depreciating right from 1973 when it was created is a good indication that what is calculated as profit will actually be otherwise after few years. I am still surprised that some of my friends are making use of fix deposit to think they are making profit, but many of them are not into one way of making money though.
I remembered my dad told me one thing many years back which is actually true, that what we use money to do is the value of the money we have. Keeping fiat is one of the wrong way to follow, if the money is not used for business, having it in fiat will be of depreciating devalue.