Having great enjoyment with the split tab groups I'v come to a
realization of one concrete reason why the eclipse perspectives provide
value. In each of my tab groups I was doing some complex refactorings. I
had really good reason for having some files in one group vs the other.
Then I had to do some quick debugging to check out a problem. I'm
cruising up and down the stack trace and in no time I have ton files
open in my tab group. Now I'm done debugging and I have to clean up the
mess. With eclipse perspectives I would have had a sandbox in which to
do the debugging. That debug sandbox/perspective would have left my
editing environment just the way I wanted it.
Maybe when tab groups are more powerful features like closing only
non-pinned files in a group, or unlimited number of groups, or named
groups will provide a similar isolation.