They aren't talking a out safety, they're talking about efficiency and accuracy. A boost converter is inefficient and you don't have power to waste like that in a watch. And electrical noise perturbs the timekeeping parts.
However your comparison to incandescent and your point about the momentary nature are both valid I'd say. If they had magic, they'd have used it. So they took something fundamentally inefficient and added engineering to make the best of it. A bad thing, done as well as possible,
You could say almost the same things about incandescent. It's not electrically noisy, but temperature sure does perturb the timekeeping, and incandescent definitely wastes power. Especially if you need the filament to last indefinitely instead of replacing it easily.
However your comparison to incandescent and your point about the momentary nature are both valid I'd say. If they had magic, they'd have used it. So they took something fundamentally inefficient and added engineering to make the best of it. A bad thing, done as well as possible,
You could say almost the same things about incandescent. It's not electrically noisy, but temperature sure does perturb the timekeeping, and incandescent definitely wastes power. Especially if you need the filament to last indefinitely instead of replacing it easily.