Tertiary sources have always been, in most venues, "acceptable" only as research tools to find primary and secondary sources,
(Oddly, though, its become common in the last few years for even reputable news media sources to cite Wikipedia as an authoritative source. I don't see that really as progress in Wikipedia's acceptance so much as a sign of the increasing laxity of standards in journalism.)
That said, Wikipedia is untrustworthy. It's a great way to quickly learn about ideas and vocabulary in a field, but it's riddled with misconceptions, misinterpretations, deceptive slants, and other errors. It's important to treat it with a healthy dose of skepticism and base research work on original sources instead. Regardless, though, it's an amazing resource that I'm sure has accelerated research productivity at all levels.
It's a great way to quickly learn about ideas and vocabulary in a field, but it's riddled with misconceptions, misinterpretations, deceptive slants, and other errors.
In other words, it's an encyclopedia.That's a really good lesson about sources in general. One can't even trust a primary source, except as an indicator about what someone at close hand thought to write down; it and everything which references it will have biases, slant and perspective.
There is such a thing as truth, but it can only be approximated.
IIRC from back then it was more like "never us is as a main source" and "for [deity]'s sake don't cite it", which I think is still pretty much the case.
It was often a useful way to find other useful sources though, either through explicit links in the articles or by introducing the reader to useful search terms they'd not thought of or otherwise been introduced to, and people were encouraged to use it for that purpose (but that purpose only).
But on the other hand, I've had other professors still say we aren't allowed.
Maybe they're warming to the idea now.
Well, for academic purposes, it still is.
But then again, as then, it's still used for those purposes now, despite the policy.