Not trying to start the classic hg vs git debate, just saying that it's great to have the option.
Check our RhodeCode for Enterprise SCM tool that supports Mercurial too.
I suppose that what they are buying, among other things, is a significant paying customer base. These customers can be sold more products, e.g. Bitbucket / Bamboo, provided that Trello integrates with them well enough, or will in the future.
Just curious as to what you think Github could do to fix this. I have a list of wishes and I'm always curious what other people have.
It also means that someone submitting bugs, say from customer support, must try and figure out where the issue is in order to log it. It's a huge hassle and most just give up and ping an engineer on Slack which is incredibly inefficient.
Trello gets around this by letting you create a "master" issue and link to the individual repository issues. It means engineering can have a bug inbox and triage from there. Still a huge pain and not ideal.
Github also has the "Projects" feature, but it is useless IMO due to the above issue - I wish projects would work at an organisation level.