Thanks for contacting them.
I agree that it would be nice to have more files being created algorithmically instead of being binary. You can diff an svg image but you can't diff a jpeg. Although the svg diff could be presented better than how we currently do it.
And you're welcome, more than 700 contributors made GitLab what it is today.
I agree git-annex is the best solution for now - I just wish some effort would go into versioning binary files by creating projects that mimic the behavior of the programs that generate them in some way.
Probably the closest thing to what I am optimistically hoping to see someday is how developers save DB migration files instead of versioning copies of the database tables, and then run the migrations as part of the merge process to sync the databases.
Thinking about it more, it seems like a general project to create 'migration' specifications to generate binary files would be more appropriate than a project to modify version control.
Anyway, thanks for your work on Gitlab!