Is this a bad habit, which I need to kick?
Would you use your camera in all situations where you currently use your camera, if you didn't have UV filters?
I do this to protect the glass on the lens from dust, moisture and scratches
Strictly speaking, dust is removable with moving air, an UV filter won't make a non-weather sealed lens into a weather sealed lens, and dropping a camera with UV filter in front of the lens could actually damage the UV filter in a manner that also damages the lens front element -- perhaps even more than without an UV filter.
Also, you can damage the lens front element very, very much indeed without it being visible in the photos. Damage to the rear element is worst. Fortunately, the rear element is well protected. (For fun, do an experiment: cover the upper half of the front element entirely, you'll see from the photos you only halved your exposure and affected the shape of bokeh balls -- the lens can perfectly well form an image with only the lower half of the front element.)
So from a purely rational perspective, UV filters might not be worth the cost, and a lens hood might be a better protector for the lens front element against scratches.
For me, an UV filter was just the thing that made me use the camera in situations I wouldn't otherwise have used it. So even though I understand that it might not be worth the money in a purely rational sense, it's certainly worth it to me, enabling me to use the camera without any worry of damaging the front element. (Probably I'm over-worried of damaging the front element...)