maybe use it for playing around and learning new stuff

If you have a homelab server chances are you are able to run a VM with remote access. If that's the case then you can use the MacBook as a thin client for remote access.

I don't know anything about Mac hardware, but if it's possible to put another 2gb of RAM in there and an SSD, it should be fine for web browsing.

I did something similar for a friend. I spent about $25 on hardware to put equivalent upgrades in an old laptop that had a single core celeron processor. I installed linux mint xfce. It ran firefox fine but couldn't quite play smooth video on YouTube. It was otherwise usable. A dual core should be workable.

I see a very decent media player, maybe a PiHole, or you can add some USB storage and have a nice backup server.

Just because it won't run a browser it doesn't mean it should be thrown away.

Could be useful if you like to have something to SSH into things.

For instance, I find it useful to SSH into my desktop through termux on my phone. But using a phone keyboard for that isn't very comfortable. But yours has a dedicated keyboard.

Try installing Debian or Opensuse MicroOS without a Desktop Environment, that way you can save some memory and disk space. You can run cockpit if you want to control it through another machine. Useful if the keyboard or display isn't working.

You can use it for learning about self-hosting like setting up podman/docker or installing firewall etc. You can even run a simple pihole DNS server.

I'm running klipper for my Ender 3 with almost that exact same config on a 2008 STI IS1415. It also manages to run i3 with qutebrowser without a hiccup. Compared to the Pi 3B+ I had before, I get a keyboard and screen to control the printer without running to my desktop on the other room, and the integrated wifi is actually pretty decent, it even shows the camera feed smoothly.

Since you have already asked this question, you have no use of it. You had better sell it to someone who can make better use of it.

It's good to keep some old computers to play around with. This looks particularly old, so you could look at trying some ultra lightweight desktop environments and browsers - don't really have any current recommendations there myself but it could be fun to see what you can do with it.

Run tinyLinux

Moc, castero, pluma/texworks, and radion.sh (look it up).

Great machine for word processing.

Add in mednafen, tweak some configs, and enjoy classic emulated games.

What cant you do with it? Find out and let us know.

I'd love to have something like that (with a new battery); I'd install a headless Debian and live in the TTYs. Just like a numeric typewriter.

Looks like you are kind of limited because of the resolution. I mean, if you are downloading pictures of big black titties, on such low resolution, you can really only see the left titty or the right titty. You need more pixels if you want to see them both, at the same time. Highly recommend you upgrade to 4k resolution.

Host a website or minecraft server?