Dear Elise,
I believe this is something that should be changed. Disabling parallax effect (even though user has specifically activated it) is wrong. You can’t provide a setting that is supposed to do something, and then limit this setting to only certain devices.
1. If you want to maintain this limitation, you must then add a tooltip (?) next to the Parallax title setting. When hovering on this new tooltip, you would then add the mention “This setting will work only on devices above 1024px for performance reasons.”
2. If you decide to leave users the choice to make it work on devices below 1024px, then you should apply a distinction in this setting between Desktop / Tablet / Mobile (just like you did recently for Design Options, by providing different settings across those devices). There, users would be able to select whether they want to enable it for a certain device type or for all. But you can still add a tooltip (?) saying again “We recommend to not able parallax on mobile for performance reasons”.
I think the Option 2 is the best approach. Please give users the choice.
Thanks
Simon