This conflicts with what I thought, but I may be mistaken. The checkmark is in the 'Hosted Feature Service' column (frozen column headers would be great in the documentation, fyi).
It's from here
Could I get confirmation that the server has to be designated as a hosting server to be able to host registered map services?
Sign in to the portal website as an administrator and browse to Organization > Settings > Servers
To be hosting, the server should be added to the Portal and be federated:
Then a federated server may be assigned as hosting:
I presume that if your server is defined as hosting - it will be listed as such on your Portal Organization > Settings > Servers page.
I was actually just wondering if the hosting server designation was a requirement for being able to register GIS data to the server so it can be published as registered map services. I had thought that designating a server as a hosting server was only necessary for allowing data to be copied to that server - ie to publish hosted servers.