To address the original post, what do you do with tanks?

To me, I have fun with the mechanical intracacies you find in a full-range-of-motion tank. You can drive over all sorts of terrain. Whenever I need a diversion from my hectic life, I'll lock myself away in the workshop and tinker with some part of the tank that may need fixing or re-painting, or the look of battle damage, or whatever.

As pointed out by others, some have battle systems (like the Tamiya laser battle system), which introduces another fun aspect of war gaming with other tankers who have the same laser tag type of set up.

You can make the hobby whatever you want of it.

RC airplanes are fun too, but tanks don't crash (taking from a quote from Tom A.)

Check out the larger scale tanks too -- much more expensive but some are reasonably priced. Being heavier, they give a little more realism but also present more realistic problems, like getting them onto the work bench without causing a hernia.

Here's a shot of my 1/8 scale King Tiger in winter camo working its way through the snow.

Cheers....