This was asked and answered in various ways, maybe more than 100 of times, why don't you just search?
Investments are not meant to be held forever, people - sooner or later - will use them. Then some are already paid in crypto. Crypto is a form of money. People do spend crypto.
The problem is that some of the (too few) payment processors nowadays make it pretty much overpriced to spend crypto directly (service fees, bad conversion rates), but I don't see why people would not buy with crypto absolutely all that's being sold, including food. LN may need to start being used by payment processors though, to make this also work in the supermarket (to not wait for on-chain block confirmation times).