Because, well, I have RV Kitchen that removes the need to carry pots, frying pans and hotplates, welding rig that removes the need to carry welder and soldering iron (welding goggles should be included here too, btw). Aaand I’m still forced to carry a truckload of smithing tools - anvil, forge, tongs, etc. That’s just not fair! 
I smell something dwarfy coming on. Id love a magma forge in my RV, that when given the option will shoot out lava at enemies.
FSDYHBNDEK Im getting distracted. YEAH BRB IM DRAWING THAT.
Mounted electric forge is actually on my to-do list, as soon as I can get Cata to actually compile again (the codeblocks project in master got a little screwed up).
The welding rig doesn’t include goggles because it doesn’t need to, I gave the welding rig the “CARGO” flag so you can just make your own goggles and store them in the welding rig for the same effect, or take them with you if you wanted to wear them/use them somewhere else. If I made the welding rig just give you welding goggles when you’re near it, I would have had to include them in the rig’s crafting recipe, so you would A - still need to get a pair, and B - wouldn’t be able to take them with you anywhere else. The mounted forge will be the same way, the part itself just gives you the forge, and it will have cargo space in it to store the other tools.
I hope you’re enjoying the welding rig though, BTW both the welding rig and the kitchen unit have been improved in the latest experimental, now you can “examine” them to get the iuse menus for the welder/soldering iron and the hotplate, so the kitchen unit can heat food, the welding rig can repair armor, etc.
Great! Lemme use my iFingers on my iLips so I can iWhistle with cheers!
Even Chuck Norris has to return welding goggles to Natures Witness. And his laser-eyes stop lava.
Mounted electric forge PR is up, check it out at https://github.com/CleverRaven/Cataclysm-DDA/pull/3881. One thing I may change is creating a recipe for a special “vehicle forge” part instead of just directly attaching the electric forge to the vehicle, as this way I can’t really add any storage to it.
I think the RV forge is a great idea, but I think we need electricity generation to be rebalanced in vehicles.
Also adding in a generator component (we do mount dedicated generators on vehicles) that can be turned on that would convert fuel to electricity while making bunch of noise.
Thank you, Natures Witness!
Regarding electricity generation. IMO, latest experimental eases the situation with adding the ability to fill funnels retroactively, i.e. you are no longer forced to stay in the same map tile to actually fill the water into container. A few acid rains, bunch of (makeshift) funnels, capacious containers beneath them (gallon jugs or plastic/steel jerrycan or even aluminium keg, if you are able to find one), and a couple of days afterwards you are most likely filled to the brim with weak acid.