I don't disagree with that perhaps on actual grass turf, but it's gotta be tough on your trail toes on a carpeted or hardwood floor....
Anyway, sorry folks, kinda reading all the posts on this thread, and haven't provided my personal experience with this swing aid. I got the Planemate last summer and it's helped me tremendously. I'm 51 yrs old and basically realized last year that I had been swinging the club incorrectly my entire life (a lot of casting, with thin hits and lots of slices).
Prior to using the PM and watching a lot of youtube instruction videos, I was scoring from 100-110 range, and after the PM, I've brought down my scoring to the low 90s/high 80s last year alone. I've played about 10 rounds this season, and I shot an 82 so far. A lot of that improvement was due to the PM. As people have noted, immediate improvement on the short iron/wedge play. And then more consistent ball striking with my other clubs after doing the initial protocols.
What I've been working on this spring have been the advanced protocols. And this is where shallowing of my swing is the goal. I still have a steep swing path, causing slices and thin hits. Protocol 5 in the advanced protocols, "impact position", really gets at the rolling of the left wrist at the top of backswing or start of downswing, with corresponding right wrist bending like a waiter holding a tray over their shoulder. Basically what Dusting Johnson does at the top of his backswing - but not as pronounced in my case. Anyway, that wrist position creates the lag that everyone talks about.
That wrist position is actually easier for me with the driver/fairway woods than my irons, and where I was basically topping out at 250 yds max on my drives at the beginning of last season, I am now carrying my drive from 260-275 yds with the magical baby draw flight path with more consistency. I frequently out drive my (younger) buddies by like 60 yards now.
So, from my personal experience, I love the Planemate and try to practice with it before every round and always at the driving range.