I'm personally not a fan of GitHub actions, because of those dependencies outside your control and more because they're a pain to debug. A lot of the time, it feels like I'm tinkering with this huge script then holding my breath and hoping I got it right.

The reason I use them, however, is because its more trouble than its worth to maintain build servers for the 3 platforms I care about (Windows, macOS, Linux) myself. Especially for projects that get built sporadically. I think one reason for this pain is that while you can easily run VMs for Windows and Linux on the same host, macOS is kinda its own special unicorn and might need a dedicated box. (But even that aside, maintaining machines you don't use every day can get annoying.)