Clever little Gizmo but as you say, limited market.

Great for electricians, certainly a time saver as shown in the video.

As someone who has carefully made actual hundreds of rectangular holes for J-boxes in our old plaster-and-lathe house, I wonder how long the blades last on real, old plaster.

roto-tools already do this. Plus this only makes one size/shape hole. what about a round hole?

Really cool. Could save the building industry Now lets make a version for the American building industry shall we?

The way I did it is I mounted the electrical boxes on to the bare studs. They were exactly where they needed to go. Then when I installed the drywall board over top, I put it into place and then sort of punched it where the boxes were, so they would dent the back of the board. Then I put the board down & cut out the openings with a razor knife. Then I put the board back in place, trimmed whatever needed, and then screwed it on. Seriously - it's not a difficult job.

This tool assumes that all boxes are consistant in size.
Anyway
Why would i pay for a tool i already have? A Fein multimaster will cut any size and shape box . And changing a blade after hitting a nail is easy
The target audience , electricians in new construction, only install the boxes. It is the drywallers who do the cut outs. They already have a cutout tool.
May be useful to trades doing install of low voltage boxes after the drywall is hung, but only on a large project

In the US, the electricians do the rough install and the drywallers install over the installed and code-inspected wiring. I've watched laborer drywallers cut in the outlets by holding the sheet up against the wall and tapping the two or three places outlets and switches go with a flat palm. Then they pull it away and jam a drywall saw into it at the 4 times at each of 3 places and are done installing that 4x8 or 4x10 sheet in under 5 minutes total. Each cut takes maybe five seconds. I think this tool might slow that process down for them, but might be handy for the DIY market with deep, deep pockets. The price, of course, is absolutely ridiculous. I truly don't see a market for it, at least over here. In the UK, how do the electricians run new wiring if the drywall or plaster is already up? That would be truly time consuming.

As someone who employees electricians to cut rectangular holes for j-Boxes, I don't care how long the blades last, I am sure replacement blades cost less then the labor cost it eliminates. I’ll have to order a couple and see how they hold up.

This is nice for old work, but new work requires alignment to boxes that already mounted for rough-in inspection, so this may actually be harder that using a rotozip and a box locator.