i started making 3d models in blender in the last year. mostly just abstract images to be used as background stuff.
they're fairly easy to set up a scene, render it out while i do other work in a different program that I have to be doing anyways, and it helps to diversify your portfolio so I think it can be good.
on the other hand, rendering high quality, highly detailed or realistic models takes a lot of build time, and computer render time, so how well those pay off for that amount of work I can't say - because I haven't made anything on that level yet. also, i am using a free open source program, but 3Ds you'd have the added cost of the software subscription to factor in too, showing me at almost $200 CAD / month so it seems less feasible.