I don't think there's any "plunge" to be taken as such, seems as the kit you need for LM and VLM is kit you should have already.
The good thing about trying out something like (for example) bonnet cleaning a carpet instead of extracting it, is that you're basically pre-spraying and agitating the same as if you would before HWE. So if you don't think it's good enough, fire up and extract.
VLM (as in dry compound)... I think many people (your cue, Martin
) would say they only get it out when there's no other option, e.g. carpets made from sisal/seagrass etc