I've noticed that tripods typically aimed at video users are often 3 tube legs - top sections will be dual tubes and the extending section will be one (or some similar arrangement). (example: https://www.bhphotovideo.com/c/product/554068-REG/Manfrotto_028B_028B_St...) This seems to me to be lighter but not as rigid as typical "photo" tripods with single nested tubes - one per corner. I personally have a big Gitzo Systematic 5 to try to hold my video camera as steady as I can as it seems to me that "big strong tripod" is the best for the sort of wildlife shooting I do (very long tele lens). (example - every tripod that _doesn't_ look like that one!)
Is there some other reason beyond lightness and less need for rock-solidity that video tripods are built the way they are?