Given that the majority of us believe that Bitcoin will increase in value over time, would u want to spend it rather than hodl and let it appreciate.
Example: Let's say I purchased a car for 1 bitcoin today but next week the value of Bitcoin has doubled meaning I was probably better off using fiat.
Depends on someones mindset but most of the time on where people who do make out investment in bitcoin are most probably holding for long term because we do eventually know on whats the potential and the benefit it could give when it comes to profits which it would really be giving out that kind of opportunity for everyone who had get engage with this market and this is what makes also popular or been known due to those kind of chances given.
For me i do make use some of my coins on buying up something online which can be bought by crypto or bitcoin itself but not on the extent for me to use it all as long i do make it out through fiat then i would be using the traditional way.