I'm not 100% sure why they're so sought after, they're less than £100 new so can't imagine they're worth much sold on. My theory is that the thieves are either trying to immobilise the bike by removing the electric assist, in the hope that the rider will leave it unattended so that they can steal it. That or they're hoping to find an unattended bike later on that they can cut the lock of and use the head unit to ride off with it. Both theories might be total bollocks though.
I'm not 100% sure why they're so sought after, they're less than £100 new so can't imagine they're worth much sold on. My theory is that the thieves are either trying to immobilise the bike by removing the electric assist, in the hope that the rider will leave it unattended so that they can steal it. That or they're hoping to find an unattended bike later on that they can cut the lock of and use the head unit to ride off with it. Both theories might be total bollocks though.