It's a little confusing from the page, but you can't actually use those hourly in terms of spinning them up on-demand for a few hours, because you pay the € 209 - 1499 setup fee when you provision one. They're just showing the monthly price broken down into an hourly price.
They're great servers, though, I have a whole fleet of them.
I understand that managing hw can be time consuming, but if you built a similar machine it would get paid off in ~18 months.
I think the point the OP was making was that you can rent this for a couple of hours when you need it, and then it makes sense. If you are using it say 2 hours a week (or even 5 hours a week) it's going to be much cheaper than building your own hardware for a long long time.