For scale type or nice sport flying stuf - sure- go for em -
It's fun to experiment

I pondered that some may think they replace the force needed to drive surfaces against heavy aerodynamic loads
Having said that
On ailerons which are joined (left to right )
The stick (servos) forces can be reduced to -0- or less (not a good idea )
stick snatch can occur
Aerodynamic aids such as these type tabs and/or spades can be a great aid - or a real problem