It is rare to get the switch to fail just because of the ignition current. The ignition circuit is not even fused as it is a reliability issue, dead fuse / relay = stranded CJ.
It is also means any future owner will curse the PO (you) for putting in a relay.
However there are plenty of circuits which would benefit from relays and heavier power and return cables, lights being a major one. The voltage drop along those undersize wires kills the lights.
BagusJeep lives in Bali.
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE