I've said it before elsewhere but I'll say it again here. It really depends on what you want to do/be/achieve.
A lot of people see themselves having careers as comic artists or concept artists or whatever. That being the case, I definitely think you should learn the fundamentals of character and background drawing the 'old fashioned' way, whatever that entails. You'll need to be proficient with gesture, anatomy, expression, perspective etc.
If, on the other hand, you just want to tell a story via the medium of webcomics, do whatever the hell you want. Whatever the hell works. Whatever will get what's on your mind on to the screen. 3D programs are just another tool, like a ruler is a tool for straight lines.
Personally, I come from a more traditional background, so I've done all the legwork. The Loomis method, 1pt, 2pt, 3pt perspective drawing, life drawing, studied gesture, painting etc. I know the ins and outs to a degree that can get me by. But when it comes to my comic, I just want to tell my story in the fastest way possible. I don't have any dreams or visions as working as an artist in any capacity. So I use these programs all the time. They're great. You can set up an entire scene pretty quickly, change camera angle, change camera, play with the lighting, and of course, get perfect perspective every time. Most importantly to me, I can eliminate the sketching phase. I go straight to inking now. It's a huge time saver.
Another thing that it saves on is re-drawing. I very rarely have to redraw something now, whereas earlier, something wouldn't look right, and I'd get frustrated and overthink it and waste so much time on that.