> every time I use AI for coding, to some capacity I'm sacrificing system understanding and stability in favor of programming speed.

Sure, but couldn't you say the same for letting other people contribute code too? In either case, you make the choice of how deeply you want to review it. You can ask the AI or the human to explain things that aren't clear.

For me it's case by case in either scenario. Sometimes it's not that important to look closely at a specific subsystem that's self-contained or just simple, other times I need to carefully audit whatever touches a different system. You need a good sense of the existing codebase/architecture in the first place to make these determinations.