Server from desktop components. Limits of application?

Question

Server equipment

Good day to all!
Not so long ago I wondered: what are the limits of application for a server assembled from desktop components? After all, it is not always economically feasible to use a real server.
I ask you to refrain from commenting, saying that the server from the desktop is not true. A company does not always have money for a normal server, the price of which (and for components too) is several times more than a similar solution assembled on a "desktop".
For myself, I see the following applications:
1. Test environment for testing and catching errors
2. File storage not loaded by I / O, like backup storage for a system like Veeam, where backup copies are dropped, say, once a week
3. RODC domain controller, provided that in the event of a failure, communication with the main DC will be
4. Services that do not require 99.(9)% availability
5. Personal server, but which hosts, for example, a personal blog (included in the .4)
I would also like to know the opinion of those who worked with such "servers". What are the limits of application of this solution (to what extent is it possible)?

Answer 1

If you are satisfied with the price / quality ratio, then why not. The main thing is to correctly assess the risks.