Absolutely you are missing some things about low power variables.
First off the objective out (aka the eyebox) changes as you rotate through magnifications.
Objective diameter divided by magnification = obj out. So a 1-6 x 24 at 5x has a exit pupil of 4.8 mm. Not ideal for low light.
The reason you would be concerned with exit pupil is that in low light you want to adjust the maginifation until you reach an exit pupil of around 7mm to permit the best light transmission possible to your night adapted eye.
So at around 3x the image projected into your eye will appear brightest in low light since the diameter of the objective out will match the diameter of your 7-8mm pupil.
Furthermore, with a second focal plane reticle which features a BDC, you can use a tool such as strelok to identify magnifications where your loading best mstches the drop.
For example, my old Razor HD2 was a perfect match at 6x for my 75 grain loading, and at 5x it was a perfect match for my 69 grain loading, and as a extreme example at 3x the optic matches a supersonic 300 blk loading at 3x.
People like to say that they never use the in between magnifications, and that may be true... But that's because they typically dont know how to take advantave of the full magnification range of their variable.
I used to use my cat tail in such a manner that i could position it so that it bottomed the optics rotation out at 3x for example.