Tourism is very useful even when not going for a Culture Victory.
The worst UA in the game is Venice's inability to make settlers. A UA that is actually a detriment. Ghandhi's double unhappiness from newly founded or captured cities is also quite bad as it prevents them from getting a quick start and snowballing.
UA's which are irrelevant or weak are much preferred over any that are actually a detriment.
Ghandi UA is awesome in the mid game and late game. It is tough to found a religion but otherswise its awesome!
Venice is just a different type of play-style. If you like settlers dont play Venice.
France was awesome with +2 culture in all cities. Strong 3 city start with liberty. Now its pigeonholed into Culture Victory. Btw how much can this UA yield "reasonably" on deity? I havent played Deity with France but hows the Chateau and Musketeer? France was awesome in Vanilla with the Foreign Legion and +2 culture!
When I'm not going for a Cultural Victory, I don't waste my time on Theming bonuses (France's UA bonus). I just bulb my GW's for their Political Treatises and my GA for their Golden Ages.
It's easy to go 4 city (or more) Tradition with India, and it won't be long before you're swimming in happiness. The Grassland start bias means that Delhi should get big pretty fast. India's UA is actually not bad for peaceful play and I wouldn't consider it a handicap like Venice's inability to settle/annex.Even when going tradition you want to rapidly found your first 4 cities. If Gandhi attempts to do this it's going to be bad news.
Tourism is very useful even when not going for a Culture Victory.
https://youtu.be/HvgyqhmoRCw
Iroquois have the worst UA as it implies it gives much more than it does.
On the thread title, no. The worst ever is Mongolia's, which only provides a combat bonus against city states.
Venice is so terrible that NQ actually deleted them from multiplayer games. So no, they're horrible.
Civ is about snowballing, abilities which allow a jump start are the strongest in the game because those early leads end up being larger later leads.
Gandhi can not rapidly found cities nor take cities by war without going massively unhappy. This is very bad. you can't wait until all of your cities are size 15 to start getting a benefit. That's too late.
Even when going tradition you want to rapidly found your first 4 cities. If Gandhi attempts to do this it's going to be bad news.