Limit Constraints with same value for min/max

Limit constraints (location, rotation, scale...) have minimum and maximum values. I happen to use these many times as a single value limit, to have the ability to easily turn on/off or switch between transformations. To do this I have to enter the same value in both min and max and constantly have them in sync when editing.

It would make life a bit easier if there was an option to enter just a single value. Maybe something like this:

thanks