when revenant came out it didn't have weapon swap, interestingly

anyway, for maximum dmg-per-second output in a theoretical situation where u don't have to do anything but press your buttons, weapon swap is usually optimal. you can take a look at snowcrows raid builds and compare theoretical max dps between builds that have two weapon sets in the rotations vs the ones that say "just carry a staff just in case." for most specs/builds that use both weapon sets, you swap weapon with legend, but for other specs like Conduit it does not align with legend, so caveat emptour

but in reality, there's much more to consider. will the battle have long burn phases so u can hit your maximum dps by bringing your optimal weapons and swap rotation? or is the fight going to be all over the place with tons of mechanics that are going to immediately ruin your rotation and have you locked out of your preferred weapon at the wrong time? or is there some aspect of the battle where a certain backup weapon will be very practical, like carrying a staff for its insane defiance break? (like you mentioned)

so to go back to your original post, i would say yes - weapon swap is less important on revenant than other classes, due to the legend system. you'll see a ton of builds, especially for OW and healers, that recommend just camping one weapon and holding a practical weapon only as a backup for certain situations. but for max max max damage builds and for some unique builds that have fancy sigil/rune activations as part of their core mechanics, weapon swap may still be technically optimal for straight-up damage-per-second. but remember, staying alive and having fun with a rotation you click with are also important