I never really saw a need to have one of these myself, but with that detailed animation I can see why they're well-liked with a lot of people.
When there ain't many new inovations they gotta hold onto what they can..... It ain't anything I'd be interested in. Each to their own.
The stihl 2 in 1 is all I used till I bought the Tecomec Super Jolly grinder. They will make a nasty sharp chain if you keep your angles right. I ended up having to remove the raker files and do those on a seperate operation because the way I pushed on them caused them to be a bit to aggressive. I ended up giving them all away.
I like my Stihl 2 in 1. Simple and effective. I only have it for the .375 chain as its what I use the most of. Im know a grinder or other methods make a chain sharper, but I'm content with it. Seems I dull them faster than I can sharpen them!
I have two for .325" & 3/8". They are gizmos that were easy to rationalize. I've used them a couple times. I, too, felt they are too aggressive with the rakers. I need to take the files out of them & chuck the holders.
There is a YouTube vid somewhere that illustrated why they they make a chain aggressive. I forgot about that till just now. It's not just me. Lol.