The bit that you’re taping on the rim isn’t usually flat. Although your rim measures 22.4mm wall to wall, it dips in the middle where the spokes sit.
That’s going to reduce the effective width of the tape. Once it’s applied, measure across the tape and it’ll probably only be covering say, 19-20mm of the rim leaving a mm or 2 gap either side.
The issue here is that when you come to fit the tyre, there’s a good chance your going to squish the tape which could cause it to
a) not seal
and
b) the tape could come unstuck once the tyre is on.
If the tape comes unstuck and lifts, it won’t seal. Also, even if you don’t squish the tape fitting the tyre, you’re relying purely on the sticky part of the tape to hold it to the rim (which to be fair, it should do. That’s kind of it’s job).
Technically, yeah it’ll probably be fine but if you use wider tape that extends up the inner wall of the rim, the bead of the tyre will help to keep the tape in place. In that situation, you got the tape and the tyre sealed against each other. If there’s a gap between the bead and the tape, you’ve got the edge of the tape as a possible source of a leak.
Saying that, I used 29mm(?) tape on an i30 rim and it was fine even though it was nowhere near the wall of the rim.
Not endorsing going against the manufacturer’s recommendations obviously, but I didn’t die.
