Fair enough. It's also very easy for people to treat what she says as gospel and go "I must not go to a conventions because this very knowledgeable person who has much more experience than I do said they're not useful. So therefore they must not be useful."
It's somewhat circular reasoning, but my view would be: if you're so inexperienced such that you will blindly follow her advice then you should blindly follow her advice. If you aren't so inexperienced such that you don't blindly follow her advice then you're probably OK to not blindly follow her advice.
This is basically true for every field ever. Generally recommended practices are most important for beginners. Once you're experienced you can start recognizing when it isn't applicable. Beginners oftentimes aren't experienced enough to apply nuanced advice, and nuanced advice oftentimes is masqueraded as general, rather than nuanced, advice.
Somewhere inbetween people might get lost but I feel like approach this gets the majority of people on the right track.
But in this case, there are a lot of somewhat experienced people who (mistakenly) think conferences are likely to be valuable. Those are the folks who would be wise to listen to such advice.
Except that you'd be better off following that knowledgable person's advice. People think it goes both ways but it generally doesn't. And that's the trick.
If someone is really going to take the advice of a person they've never met so completely literally, without considering its nuances, then I suggest that they're headed for failure anyway.
Sure, it's easy to treat it as gospel (it's also easy to not think about what you're doing); doesn't mean it's a good idea to do so.
Ay, but it's kind of the like the road out of a forest fire. Sure, you can go both ways, but if you don't know what the hell you're doing, or are even experienced, but not an expert, best to follow the directions of those around you.
It goes both ways.