Especially seeing as you can outright have a full, tiny VPS 24/7 for $2.50/mo or $30/yr from Vultr. I suppose there's a value add in terms of not necessarily needing to setup your own install, but if that's something you're comfortable with I don't quite see the point.
You're right, this is more expensive than VPSs alternatives.
We assumed commercial use cases for that price so the benefits of not having to deal with servers complexity + access control + etc.. are quickly paid back.
For hobby projects, we are thinking of creating a free plan
It is definitely the easiest way for Python code. Just paste your code and thats it
Full disclosure: I made this product. We are a YC company