There's nothing either new or unique here. Both Metabo & AEG were making (German) cordless sanders over 30 years ago, albeit with a mere 9.6v of Ni-Cd "power", which was the norm then. Since then others as previously mentioned have tried also, most notably Makita (arguably the world's cordless tool leader).
There's likewise nothing new with having an AC mains powered cordless tool battery interface either. DeWalt had one years ago, and I seem to recall another whose name currently escapes me about 20 odd years ago too. Makita perhaps?? Rothenberger, the high-end German plumbing tool specialist also had a high current version that was used on their AEG powered previous-gen. swaging, compression and flaring tools, which conveniently fitted the entire 18v AEG & Atlas Copco ranges too. Notably, it was sufficiently heavy (in both "duty" & mass) to power even their grinders & SDS hammers too! There's also the current DeWalt Flexvolt AC mains tranny too, imminently to be released in a 220/230/240v variant.
What Festo/ol has done is to bring it all together in a small, compact, lightweight & low powered package. Smart move, & long overdue in the power tool world. I would absolutely hate to try to use a handheld Flexvolt tool all day long fitted with either one of those monstrous 6.0 or 9.0ah batteries with their "low-tech" cells or an AC converter. Maybe if I was a young, strong & stupid teenager again, but not these days.
That it's also yet another unique battery interface within the Festo/ol stable is another exceedingly smart move, too. The new interface is key to the platform's success: a beautifully designed, lightweight fairly ergonomic (for a sander) package, which can presumably be comfortably used, one-handed if required, for extended periods with regular breaks incorporated for battery exchange, or not if used with the AC adapter.
I can just see the whinging complaints arising if some clown succeeded in fitting the tiny, lightweight, low powered mains adapter to a medium or even worse a high-current tool such as a drill, saw, SDS or some other future even more current demanding tool like a grinder, SCMS or disc sander and burns out either the tools' EC motor, the electronics package or the tranny itself from such wilful abuse.
Yes, some power tool users would be idiotic enough to try! Hence the new (preventive) interface.
Industrial cordless tools from other manufacturers are these days drawing levels that are approaching 70 Amperes! That's hard enough on a battery package that's designed to cope, and would require seriously heavy duty transformer windings & rectifiers to convert from AC mains to low voltage DC current. To put that pressure of current through one of those tiny, super efficient Festo/ol sander adapters could possibly turn it into something approaching a heating element in a stove, with an effective service life of mere minutes I suspect.
It's ideal for the low current demands of a sander. Maybe even an LED light, too, perhaps a (small) jiggy, or even a lightweight but gutless drill, but for grinding, sawing, stirring, auger bit & steel boring, disc sanding or chiselling & chasing something much, much bigger, more powerful & "stable" is required.
