> For most games (especially a "2d hide and seek") you drop a zip file and press a single button on your dev console to publish
If you read through the actual pipeline, you'll see it's not just "drop a zip file and press a single button". Firstly, you're missing everything that goes before even having a ZIP file, making that process reproducible is valuable regardless of what you do later. Secondly, doing this for three platforms would mean repeating the same thing three times, in slightly different ways. Automating it just makes sense at that point.
Overall, building and publishing a game via automation just brings about every benefit from CI/CD, just to a "game development" context instead, so you'd do it for the same reason you'd automate any software release process.
If you read through the actual pipeline, you'll see it's not just "drop a zip file and press a single button". Firstly, you're missing everything that goes before even having a ZIP file, making that process reproducible is valuable regardless of what you do later. Secondly, doing this for three platforms would mean repeating the same thing three times, in slightly different ways. Automating it just makes sense at that point.
Overall, building and publishing a game via automation just brings about every benefit from CI/CD, just to a "game development" context instead, so you'd do it for the same reason you'd automate any software release process.