I never had to do that with dollars." THAT'S BECAUSE YOU HAD NO GAINS BEFORE.
Read my post above this one, so you can have an epiphany.
The issue is that gains impact tax brackets and credits and all sorts of tax planning.
So you can't just take all the gains you can get.
You have to restrict yourself to scenarios.
This ruins the timing of being able to spend money when ever you want to.
At least this is how impacts some people. Maybe your tax situation is different and you take all the gains you can get, because you are in an investor class. But the common man is not. He has all sorts of things to balance, such as reporting his unemployment assistance, tax credits, solar installation energy credit, alternative minimum tax, etc....
Let's just compare the same person spending dollars vs spending bitcoin. Their tax situation is exactly the same except for a small amount of CG on the bitcoin they spent. How is paying CG worse than having no gain at all?
If you expect the CG to be significant, that means they must have held bitcoin as savings or investment, and not spent it before their next paycheck arrived.
Edit:
Now that I see your other post - I'm not a tax expert, but I have yet to see one tax credit that is all or nothing based on some income threshold. Obviously that creates perverse incentives to avoid going over the threshold. However, in the US at least, none of them work like that, or if any do, they're so uncommon as to be irrelevant to bitcoin adoption.