I often have work that I do offline, and I disconnect the internet so as to avoid having to use willpower to stay away from the internet.
I'm sure they're aware it would be useful, but concluded the number of users it would apply to doesn't justify the effort. But, in case they're considering offline support, wanted to add my anecdote.
I don't necessarily need to access all my boards and cards while offline, I'd like like to be able to add cards or modify cards I had open without losing those changes.