why?
there is no reason to level people beneath your bench people. if you are experimenting in using someone then make him visible then level all levels pretty much only him because he's sooooooooo cheap compared to everyone else who is already pretty much nearly max level...
if level all leveled all 90+ crusaders then the majority of people would complain because nobody in use would get leveled at all and all your gold would be wasted.

you mean idol gain, right?

Right idols, don't type when tired :)

And yet, gold is spent on locked visible crusaders, I mean, ones who are on missions. Are you saying that the gold spent on their levels is wasted?

So much gold is just wasted at reset anyway so why not level the mob in the bleachers? Yes, it will not get you anymore idols per reset since idols are based off of the 'saders that are currently sitting on the bench and levels on 'saders in the bleachers do not contribute.

Honestly with how gold and 'sader levels increase there would be little difference between leveling all on bench and leveling all(both on bench and in the bleachers). Just like there is little difference between leveling only 'saders in your formation and using the level all button.

I view this as suggestion as lovely QOL feature that would make building and experimenting with formations and switching from your instakill formation to your gold or wall formation much more streamlined.

@icebergak1949

There is no need to level all Crusaders of the same slot/bench. Only the one you have visible on the slot will contribute to idolgain. It's always easier to explain with examples, so here we go:

Slot 1 is the "clicker" slot.
In there you have Bush Whacker at 5000 levels.
RobotRabbit has 2500 levels.
Warwick has 2000 levels.
Slisiblyp has 100 levels.

If you reset, this slot will NOT contribute with 9600 levels. It will only contribute with the one you can currently see. So if you have Bush Whacker visible, you will get 5000 levels from this slot. If you have Warwick out when you reset, you will only get 2500 levels.

So, before you reset, you should only level up ONE Crusader per slot. It's a complete waste of gold (and potentially idols) otherwise.

Note that even if Crusaders are on missions, notice that you can still level them up? These Crusaders' levels WILL contribute to idolgain upon resets.

As a tip, check how many idols you will gain (and how many Crusader levels you have) on the reset-button. All what I said above is something you can check out for yourself just by checking the reset-button before and after swapping out Crusaders and such. Experiment by yourself and you'll see what I mean!