I think that possibly you're thinking of our stance towards questions asking for guides: we're not a link aggregator, but in this instance the guides exist on Arqade, rather than an answer being posted forwarding somebody on to another site. There is a great difference between somebody posting "Yeah, go to this site and read the guide" and somebody posting a guide on our site.
In this instance, it's not off topic: each question is about a particular problem being experienced in a game which can be definitively answered and that do not result in extensive list answers.
The reason I've been writing guides on Arqade and not on Steam are as follows;
There's no reason not to create guides here, one guide per situation keeps the scope limited and the multiple answers per question allows multiple methods of completing the map to be posted if others want to contribute, with each potential tactic being voted upon
Better SEO - if you search for "How can I pull off a Bank Heist" on google, you will get Arqade as the first result. It's easier for the rest of the internet to find the information if it is posted on Arqade rather than on Steam
Less noise - Stackexchange is about less noise and more signal, Steam is full of noise, a guide posted on Arqade will get updated if patches change stuff (I will see to that if others don't)
A previous conversation discussing creating Q&A style boss tactics for WoW bosses happened in the bridge (about 10 lines of conversing about how guide-style posts would work) in the past but I never got around to writing guides for WoW before I quit the game, I am, however, applying the same thoughts to writing guides for Payday 2 heists.