It wouldn't be universal to the project, they have considered these options before but held back on it. There's an explanation here:

https://x.com/GrapheneOS/status/1685398977972244480

This doesn't mean to say I'd be against running one just for me. MetropleX runs his own lightning address for example. Once I get a domain it will be in the first three things I consider starting up. Also strong doubts individual members would have their own wallets as @grapheneos.org but rather a single address for project donations as a whole. The developers are paid employees, community mods are volunteers.

The project is very interested in accepting lightning but we need it to be very secure, long-term and scale reliably.