Pluggable terminal connector long term reliability
Never used tinned multistranded wire in a compression type connector such as these. The Solder will creep over time and the compression force will weaken. Making products with this particular type of connection will fail safety standards.
All connections should have some kind of physical/ mechanical strain relief and not rely just on the interconnect. The crimps offer a strain relief so are a good method - one seen in better quality installations.