What's the difference between a shop vac and a wet/dry floor mop vacuum?

Traditional shop vacs (Craftsman, DeWalt, Stanley, Ridgid) are corded canister units built for heavy debris, water, sawdust and jobsite use. Cordless wet/dry floor washers (Tineco, Dreame, Bissell CrossWave) are upright units that simultaneously vacuum light debris and mop with clean water, optimized for finished hard floors rather than construction messes. They are not interchangeable, and specialist subreddits repeatedly warn against using floor washers for serious wet-plus-dry debris together.