I always solder & heat shrink. For a quick get me by I will crimp.
While I am no professional, I know a few ... they solder &heat shrink also.
When I went to a community collage to be a electrician ... I dropped out.
The instructor explained he could tie a knot in the wires and make it strong enough to hold.
It was the solder that maintained the proper resistance flow of 2 wires being connected.
Imagine a crimp on splice, you insert both wires in the end, crimp them together. Now your 16 AWG becomes a 10 AWG then back to 16 AWG again.
Pretty sure a 1938 Ford tail light wire wont care
But something more delicate like a motor or controller it may care.
Also have to remember there is different quality of wire. House wire is single strand.
Automotive wire is multi strand. Then some areas like inside a distributor you want a very flexible wire ... just a guess here, thinking it has more copper strands then normal?
Then there are different types of solder. You have solder to put your copper water pipes together under your house, and it does solder wire. Not really the stuff you want to use on your car wiring or on a electric motor.
Solder is fine, just select right products for the job.