Yea, they are very useful for small sites.
The bigger problem for me was to find a free backend hosting service, I've only found 3 free and all of them were pretty limiting: Heroku (the instances go to sleep and take 30+ secs to wake up), IBM cloud (256MB memory limit), Azure (pretty complicated, need a credit card for the free tier).
I was looking for a solution where I can host Java Spring/ASP.net toy projects easily and none of them were satisfactory