If you have wear on the thumb...that is an indicator of an active right arm from the heel of the right hand against base of the left thumb...this is normal ...though usually for hitting....
If you you have wear on the heel of the left hand this is an indicator of an active left wrist uncocking downward causing a change in the angle of the left arm and clubshaft...this is normal...though usually for swinging...
Now what if you have wear in both places?..perhaps you alternate procedures or you are "switting" or neither...perhaps pecking, icking, pawing or pausing??????????
According to Golfdom...there should be no wear...
To me no wear...no presssure...
No pressure ....no compression....
Golfdom would rather you Sustain the good condition of your brand new glove.... than to Sustain the Line of Compression( Bullet Holes through a Baseball)