I don't know if it's fun, it doesn't even matter, maybe it is, maybe it is not.
I just feel it would be stupid not to "abuse" the system and pwn singleplayer thanks to grinded materials from MMO.
It feels like cheating and Bioware discriminating people who'll singleplayer only again for sakes of their precious MMO gambling boxes.
Again, thanks to Bioware boards shutdown I can't put a direct feedback to developers on this stinking design. All I can hope is that reviewers do not forget about it while showering the game with (paid probably) 10/10s. Yea, I can always write to Jim Sterling, but cmon.
Maybe I'm wrong. Maybe they did think about this and maybe there is a cap that prevents pouring tons of grinded materials from MMO into the campaign. Or some other mechanics that will make sure you can't go no_challenge cakewalk singleplayer. But so far they didn't mention it anywhere.
After horrible ME3 cross SP/MP design and even worse MGS5, protecting the singleplayer game is so important to me that if such cap exists, I'll preorder the game this very moment.