Today I got a router bit spindle for my simple shaper - no sliding table nor
power feed. I have some router bits, mainly 1/2" shaft. There are many
shaper cutters that are the only choice for a cut, such as glue joints or
double lock miters. Then there are some cuts that you could do either by
shaping or routing. Is there a simple set of "rules" that would help me to
decide when I should invest on router bits, shaper cutters, or both? My
main interest is in the accuracy and quality of the cut and secondary
interest is in the safety of the cutting operation.

Some counterexamples would be nice to know for cases where in theory, you
could do the cut by shaping but routing is the right choice and vice versa.

Cheers, Ollie