As long as I can remember I’ve been buying random domain names I think are clever, or funny, or would work for some project. In college for a couple months, I made a rule for myself that every time I went out to party I had to buy a domain name. Not sure the logic that brought me to this, but it was something about adding a little asset, albiet a stupid one, and making going out a little more expensive.
Domains are like $10 to register, ~$12/yr to renew, and ultimately are like a little piece of internet real estate. If you have a domain someone else wants – you can sell it to em. Pretty simple.