Okay, first things first. Artemii, were and still are wildly popular.
There was a time where triple artemis junkers were the norm.
(The shatter damage could strip the hull enough to get a long range kill.)
Nowadays, it can be seen, on hades/art/art/[close range guns] mobulas, hades/art/art/[close range guns] junker, hades art pyras, sometimes on a spire, rarely in a squid, sometimes i've shot one on the top left of galleon.
However the difference: Artemis do explosive as primary damage, and shatter as it's aoe (secondary) damage.
This paired with it's long range means it is a light gun with long range power to kill, as explosive is strong vs. perma hull. However due to it's shatter aoe damage, it is effective vs. components and can (and almost always is) used for disabling guns/ engines at a long range.
(As shatter is aoe, burst ammo increases this radius making disabling easier [higher chance of hitting a component] and increases your ammo- great for disabling!)
The banshee, since the update does explosive as it's primary, and now fire as it's secondary (previously explosive.)
This makes it effective at harming permanent hull (explosive) and and now effective at damaging balloons with it's secondary damage, fire since it does 1.5x damage vs. balloon. Note Burst is not used for it's secondary AoE damage as hitting a balloon is pretty easy. And it makes shooting it really slow.
Hope this answers your question.