The dollar value of that crypto price is variable. Even if the price in crypto constantly updates, the cost to you in dollars is always in flux. For no discernible reason a cryptocoin can fluctuate in value.
Today one coin will buy a coffee while tomorrow one coin will buy a PS5. There's no incentive to transact with crypto if there's any assumption the value of that crypto will go up tomorrow.
For a seller they can get wiped out if they accepted payment for coffee in crypto and then the value of that coin tanks.
Knowing the crypto price is immaterial. You can never know what the value of the item will be. It's like paying for everything with lottery tickets.
Nevermind that most crypto systems are purposely deflating, because the whole point is to reward the people who were there first. So ANY purchase of coffee with crypto is self defeating. Your money is ALWAYS more valuable tomorrow. Actually smart people have known for a hundred years that's a stupid way to run an economy and people respond to it by hoarding and it basically eliminates economic activity from happening at all.
Yeah there this this problem where sellers want to acquire appreciating money and buyers want to dispose of depreciating money. So, the goal is to somehow balance it out so that you have money that both seller and buyer want to use. The rule of thumb is 2% inflation. Of course you might argue that 0% inflation is better and -2% as a demurrage/negative interest is better because this means prices stay the same and savings are not devalued.
Please educate yourself on a topic before pretending you know how it works.
Ethereum is deflationary ONLY if there's high economic activity. If there's lack of activity then it's inflationary. You can think of it as self regulated easing and tightening without the need for a central authority like the FED.
That said, you can also use a stablecoin to make payments.
Today one coin will buy a coffee while tomorrow one coin will buy a PS5. There's no incentive to transact with crypto if there's any assumption the value of that crypto will go up tomorrow.
For a seller they can get wiped out if they accepted payment for coffee in crypto and then the value of that coin tanks.
Knowing the crypto price is immaterial. You can never know what the value of the item will be. It's like paying for everything with lottery tickets.