In my upcoming webcomic I traced over a pic of a Prius. There was just NO WAY I was going to gobble up tons of time trying to draw this thing on a screen(I'm drawing the comic digitally). I think I skimped enough on it so that it could fit with my art style...for the most part, I usually draw out most of my backgrounds.
Like a couple other posts stated- you've chose to be a comic artist. Doesnt matter whether you're a industry pro, or small independent artist- as webcomic artists you're trying to get your page/story done within a certain time frame, and unlike industry pros who have been around for a while, we dont have tons of books and/or reference photos...so you have to do whatever you can to give you an edge towards getting your work(s) done by a deadline. If it's using 3D programs, tracing a certain pose, or using model pose material, then it's helping you get the job done.
In your spare time if you wanna get better at doing art the traditional way, then do so...but if you want to make a job or make a pretty penny out of doing comics, then you better be willing to take some shortcuts to get the work done.