Why non inflationary currency can work

An argument against Bitcoin often is , that nobody wants to spent it, since it gains value and why would you spent that right? So people are assumed to spent less or not spent at all if their currency does not inflate. That is BS imo.

Well let me tell you what happened to me this week:

I wanted to book a car and wanted to pay it with Bitcoin Cash over CheapAir.com , BUT.. yeah.. I also trade and was long Bitcoin Cash, so I though lets wait at least two days more, I was hoping for BCH to break 880$ and have a big push after that. Maybe I could have made like 40% over a couple of days, maybe not, my edge was far from that as it also can loose value as it did. If I am lucky the edge on a trade I take is maybe 1.5% , that would be huuuge.

The story here is not that Bitcoin Cash lost value in those days, but that the price for the car that I wanted to book TRIPLED in the time I did not book it!
And you know what, I need a car over the weekend, so I am still gonna spend, no matter what bch price or the car price did pretty much.

Another example is that people ARE buying smartpones computers, tvs and such.. a LOT of things loose a LOT of value over one year, why did they not wait to spent it one year later?

And again, the ev if you are awesome at trading and soon to be billionaire anyway is maybe 1.5% per day or so. And that still is way way way more that the inflation rate of a given currency! 2% per year is nothing, nobody cares about that.
What people see are the storys "Oh if I would have not spent, I would have X" thats bs, it could have lost value too.
It is not the missing inflation that brings up those stories, but the volatility of a currency and that would be less with world wide usage.

Oh and it turned out for cars you can't really use cryptocurrencies whatsoever ;(.