As the subject suggests, the ability to use 'This' on any control would be extremely useful for at least my use case and I am sure it will at least be mildly useful for others as well. To go a little more in-depth about this, for instance, if you have a Button, and wish to use the Text attribute to update a variable. You need to specify the 'Button name'.Text to use that value, however, if you could just use 'This'.Text or something like This.Data.Text (since the actual text value is in the DATA of the Button).
TL:DR = Let controls be able to access their own values using 'This'.
BTW, I'm new to PowerApps and if there is a way to do this or if there is a reason we should be able to do this then my bad.