I'd be arguing against them because the blue shells would waste item pickups when I could use something else more. When I'm in last place I want mushrooms, red shells, lightnings, etc, anything but blue shells because blue shells don't help me at all, they help people on the other end of the field.
You won't see me in any PGC matches though, no matter which game is being played. I'm not hardcore enough anymore to get up to international level, especially not in racing games (among the hardest to learn genres IMO as it's not apparent when you make an error, in other games you get shot at or something but in a racer nothing happens except you lose at the end).