I didn't see a "toe-heel" shifter but I've had bikes with them and understand why they are not popular anymore.
So imagine putting the ball of your foot on the peg and pressing down with the heel.
Then
Shift your middle foot forward to reach the toe shifter part .
Its just easier to leave the foot in the middle and swing your toe around instead of the entire foot moving back and forth , up and down , finding the toe piece then finding the heel piece. If your foot stays put on the peg you don't have to "find" the heel or toe parts.
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My first thought was "Hay , Thats a nice Fender" .