Well, first of all, if it’s working for you, then there is no downfall.
For me personally, I can already drop fast after a Humalog bolus – or, rather, when the Humalog decides on its own sweet time to finally kick in – so if I don’t get my food timing spot-on, and I often don’t because that’s my life, then I’m responding to low alerts all through my meal. (Glucose tabs will never be a trendy side dish.) I imagine that, for me, an IM shot would turn this scenario from a nuisance into a crisis. I’m not sure if I’d want a quicker or even a stronger drop on a routine basis. So for now I’ll reserve them for correcting those highs that just won’t come down otherwise. Very conventional, guilty as charged.
Then again, I’m now doing lots of things I never even knew were possible before I stumbled on this place …