Maybe I missed some others but I really like the detachable back.
I know what the holes are for but they are really also good at collecting dirt. Being able to clean it better is critical.
29 MH/s at 60W isn't really that impressive. I know the price of current GPUs are insane, but just FYI my 3-4 years old Vegas do 40 MH/s+ at 100W or below,
and fact is also they were way cheaper when I got them.
I remember M1 did like 2 MH/s only, I wouldn't expect M1 Pro/Max to go much faster.
Plus the break even will likely take forever, or at least much longer than getting a GPU.