mines are what you're looking for in terms of hard to detect ground level AT weapons, and there's faster, better ways to rapidly deploy them

The ideal use case of these seems to be precisely as mines - I would agree that the article's presented scenario of a bunch of these swarming the enemy is maybe a tad silly (although I also feel that you're somewhat overestimating the ability of vehicle crews to actually spot these and effectively fire at them - visibility from within a vehicle being dogshit has been a problem since the very invention of mechanized forces as a concept, unless you go back to ye olde open-topped halftracks I find the chances of the gunner and commander actually managing to spot small targets so close by out of their optics to be pretty dubious - I mean, the Israelis literally had guys sneak up on their vehicles and plant bombs , vehicle optics are optimized for spotting enemy tanks far away, not this kind of stuff)

But something else you could do is just have them lay in wait for a vehicle to pass by (which has, in fact, already been developed as a tactic for flying drones, wherein they sit parked beside a road and only fly up when their operator spots a target passing by - and a ground-based drone could carry a rather bigger payload). Minefields can be deployed rapidly with modern remote minelaying systems, but they're still static - you deploy them once and that's it (and then you might find yourself having to invest a whole bunch of effort undeploying them if you ever need to then counterattack along the land you just mined after the minefield does its job of blunting the enemy's offensive). Moveable mines could provide a greater degree of flexibility.

Now, this coming from the US MIC does mean that there is pretty inevitably going to be an element of grift, but not necessarily in the "this is a completely unworkable concept" sense - most MIC grifting isn't that, it's just charging too much money and producing things too slowly. Many of the various American long-range missiles and interceptors are perfectly fine as designs - they're just too expensive for what they provide.