One reason to use them on land would be to take FRA, WFR, and SFR all at once … but it probably doesn’t outweigh the strategic advantage of sinking an extra SZ of Allied ships.
Though you have me thinking now about how many land units you can safely free up (i.e. start moving toward Russia early) by using significant air over Paris and how much difference that would make against the USSR. This would only make sense if you only do Sea Lion opportunistically and you plan an early Barbarossa.