For me it depends. If you're going to let me tinker with and modify my own equipment then yes I'd like some "fluff" details to go with it, and I'd like it to be consistent (or at least have damn good explanations for when it's not).
But do I need or even want to know all that stuff if you're not going to let me do anything with it or the game is focused on social interactions instead of warfare? No, not really. Just keep it consistent, provide enough information to know what's going on and provide more in-depth information for where it makes sense, and for those players that are interested. (The medic type character should really have more knowledge about medical things and the how's and whys. The explosives expert probably doesn't give a damn, so try to not bore your players.)

Also, I really support the idea of doing little handouts for those interested in it, it keeps the game going and people are free to skip the parts that doesn't apply to them.