I would love to be able to write a game that can netplay with other Playdates. Even just having the ability to do http GET and POST requests would already open up a lot (such as leaderboards). A unified way to start a netplay session with another playdate (via bluetooth or internet through a room code or something) would be even better.
It would also be awesome if this could be exposed to Pulp too, as an "advanced" feature. I've been writing a clone of Tetris Attack in pulp, and while 1-player mode is already entertaining, I'd love to add a 2-player mode as well.
I'm actually interested in this for non-game purposes. I want my Playdate to be my before-bed device, with its non-backlit screen. I use podcasts to help me sleep, so I'd use the Playdate to control podcast playback and selection on another device on my local network. An HTTP(S) API would be a really nice way to accomplish that
The Playdate hardware specs constrain game design and encourage simpler, more achievable products. Given a networking API, I think the Playdate would be a great platform to practice making simple multiplayer online games.
Additionally, charging for service in one form or another solves the piracy problem. Storing credit card details on a networked device would handy for users, but it opens up a lot of security concerns.