After watching the ttyrec of the bot ascension, I was surprised to see that the bot farmed on a sink, not an altar, and hence used the puddings only for item drops and not for sacrifices.
That makes me a lot more optimistic that the bot is close to being able to ascend without farming, especially since I believe its character already had multiple amulets of life saving and a bag of holding even before starting to farm.
Combat in non-enclosed spaces is hard do to ranged attacks line-of-sight, etc.
I'm slightly surprised it has taken this long to do with pudding-farming, as that lets you get plenty of really powerful items (as well as other benefits from sacrificing the corpses)[1]. There are a few parts of the game that are super hard for a bot even with the equipment of pudding farming, but I would have thought a few thousand runs would be enough to luck through them with simpler rules.
1: Puddings are creatures which can split in two when you hit them, and each new pudding will count as a corpse (which you can sacrifice to your deity for benefits) as well as having items. I don't recall all the details, but some of the rare drops from black puddings are really powerful. The idea is you take a really crummy weapon, so you don't accidentally kill the pudding and then hit it over and over again to get lots of treasure. In this run it looks like the bot used a skeleton key as a weapon.
The main deterrent for a non-bot player doing it is that it is really boring (There's a quote somewhere from the devs that is roughly "we implemented a penalty for pudding farming, it's called 'pudding farming'" Obviously the other deterrent is the prestige of beating the game without pudding farming, and that does apply to bots too.