One thing I know is that seals and o-rings work as a system, so quality of seals/ o-rings is as important as having defect-free mating components (bore and shaft.)

If sealing surface on bore and tube OD is smooth and defect-free (i.e. scratches, roundness, roughness, etc.), you should not need RTV to make the system work, period. However, if there is a minor scratch in the bore, maybe RTV eliminates the leak-path where o-ring alone can not overcome by itself. Viton (FKM) is preferable material for extra heat resistance and life, but it gets much stiffer in cold temp than regular NBR, which may result in minor trace. Then, little coat of RTV may help a bit as silicone has better low temp flexibility.

I believe it's case-by-case and really no definitive conclusion. I do not use RTV and mine does not leak more often than it should (my tranny does though......), but I can see some benefit with RTV. It's whatever works for you. Just my $0.02.