Removing the domain like this transforms it into a local link which prevents the instance redirection. Doing this will make it easier for newcomers to join your community and participate in discussions!
Those interested can monitor Github issues #369 & #1048 for when this UI bug is fixed!
There is an issue with this. If nobody on the instance of the user that clicks the link is subscribed to that community, this will result in a 404 error. If at least one person on the instance is subscribed, it'll work. In a browser. Not in Jerboa.
I suspect that this may be somewhat frowned upon. The whole point of not grabbing all communities from all instances by default is to avoid massive traffic dumps every time a new instance joins the federation. Doing this via a bot is basically the equivalent of DDOSing your home instance!
It's less bad when a human does the same thing because:
A) A human will work more slowly than a bot
B) A human will likely only do this one time and then let the system continue working as intended afterward
C) A human can be easily reprimanded and told to stop if they're causing problems
Yes, unfortunately. This is one of those situations where it's technically less user friendly to browse on a smaller instance (since large instances are more likely to already be subscribed to a given random community). Of course, this issue affects anyone who tries to visit a given community via their home instance, not just people using this particular link style.
Right now this problem is being tracked on the backend Github as #2951. Hopefully they manage to sand off this particular rough edge ASAP.