Per Ashton Crusher:
The crimps I do at home, even with a decent
hand crimper tool, I don't consider the same quality as a factory
crimp. But many of those home crimps have lasted years and years with no trouble...

On my winter bike - equipped with an electric motor - I've got 4 crimped
Anderson connectors and four solder joints.

Over five years, the solder joints have failed twice but the crimped
connectors have given no problems.

OTOH, that's just failure. The efficiency of transmission has got to
be a whole other issue - which I have no clue about.
--
Pete Cresswell