The Forma's using a capacitive grid that actually works as intended (unlike the one in the Aura One, which is hilariously terrible), while the H2O uses an IR grid.
I *think* the Clara ditched the IR grid, too, but don't quote me on that (I think the last Kobo device with an IR grid was the Glo HD, though, so that would track).
Note that I personally intensely dislike IR grids because of how iffy they are for precision one off taps, while some people love 'em because that means one less layer on top of the eInk screen.
The fact that they *require* a raised bezel because of the IR LED brackets, which end up being a dust magnet, is also a big no-no in my book.
I like my bezels flush
.