One of my bikes is QR, I’ve used the same method with it and it seems OK.
The hook goes around the QR axle, but it sits against the inside edge of the fork, so the weight isn’t really on the axle itself. Mine certainly hasn’t bent yet anyway.
It’s more of a faff for QR as you have to remove wheel, remove axle from wheel and reverse each time you ride. You also need to bear in mind that without the wheel in a QR axle you can squash the two legs together by over-tightening the QR. Just do it tight enough that the safety tabs hold the axle in and don’t worry that the cam action isn’t overly tight, it’s your fork legs flexing.
If you have the space and can’t be arsed taking wheels off I can see the merits of leaving the wheels on, but if you’d rather use the room for something else it’s much better. You can also mount the bikes up higher as they’re not as long with the wheels off and if you’re putting them up into a roof space you can go higher again without the wheel hitting your tiles.
If you get them high enough then you could build a wheeled chest to sit under them that you can keep all your tools and kit in and incorporate a step so you can reach the bikes down easier. That was my plan, but I’ve since moved them to my gable wall and use a ladder to lift them up and down, so now they take up no floor space at all.