Yeah I know what you mean, I've thought that before too.

I think it's actually more about the intent, rather than the mantra itself.
Laying in bed thinking to yourself I'll remember the next time I'm Dreaming over and over just seems to let your brain know that it's important.

You'll often get into a vivid, non Lucid Dream and within a few seconds click on and become Lucid.
If you've hit your REM period right it will be very close to when you've just fallen asleep and as you've been so determined to realise you're Dreaming just moments before, it seems to jolt your consciousness enough to question if your Dreaming or not, once that happens your in!


The other reason MILDS are such a good way to get Lucid is what you touched on before, you can sometimes get WILDS through them so it's a bit like two techniques in one.