I totally agree, and this is for several reasons...not simply aesthetics but also for their safety. If something goes wrong, I want to know about it, so easily seeing
into a cage is important to me. When you have to go out of your way to look in, you just won't do it as much.
I also prefer that my snakes get a natural photoperiod from room light, plus I believe that my snakes are far more trusting when handled because they are used to my
presence. A snake that cannot see out until suddenly you swoop into their tub to handle them has to be a little more traumatized, though the effects depend on what
species you're keeping...some just have naturally better vision.