I don't think it's a bad habit - they just have a preference for how they like their dinner, and probably not a hard one to satisfy.

I deliberately give mine a meat/biscuit mix, both from dietary recommendation and also it slows them down a bit - there's three of them, and if given meat only, the quickest eater will scoff his in 5 seconds, then try and muscle in on his brother's dinners. If mixed up, they're all at their own bowls for a few minutes at least, before the inevitable swapping.

Maybe cut down on the treats, and save them for special bribery i.e. flea treatment, going to the vets, training etc.