How can we come to terms with spending deflationary currency

One thing that I can't seem to grasp is how we can come to terms with spending currency we all seem to agree will increase in value over time. While inflation can hurt individuals depending on how much the yearly inflation rate changes, that does happen with growing economies and increased spending. Deflationary currency should be good for people selling goods since the currency used for the transaction will increase in value. However this doesn't seem to be good for the consumer, since there is a chance that over time, they had parted with too much of their money in previous transactions. Basically something like the guy who spent 10k Bitcoin on pizza.

Right now I'm in the process of buying a car, and trying to scrape together as much as possible for a down payment. So, I have decided to sell the last of the crypto I have. Right now, we're seeing a boost in the market and my crypto has gone up very much in value. I know I should sell at this time, but I had thought the same last week and now the same coins I had intended on selling have increased in price by 22%. That's pretty wild for one week. Had I sold, I would have lost out on a significant amount of money .

In general, how do we have incentive to actually use our crypto for things like buying goods? How is a deflationary currency intended to be used in a real economy? Idk. Sometimes I feel like the only thing crypto could be used for is an investment. Im obviously not an economist, so I'd love to hear other's opinions.