functionality and beauty. If you need it, get it. If you want it, get it. My Sig Scorpion is my first 1911 with a rail. I bought a cheap <$50 light to hang on it. (of course, I don't know where the light is. I used it just last night at the range, I think my son stole it.)
My thoughts were, if the light is useful, then I might upgrade to a better light. If this light were to give out, I would definitely replace with a top of the line light, maybe with a laser also. I do like it. Additionally, the light fits on the Glock rail also, so nice double duty.