I'm not a fan of this addition either. A big problem with Help chat requests is that people ask vague questions or questions that can't be understood, either due to bad english or some other reason. These questions usually end up being ignored by most people regardless of whether or not people are having other conversations in chat, but if there are other conversations in chat, the people asking those questions immediately blame the non-responsiveness on the conversations. Too many times I see a question that isn't answered due to one of those reasons, the person asking follows up with something like "stop spamming Help chat, I need help", people actually stop to help this person, only for the person to just repeat their question unchanged and still nobody answers, or ends up being answered "I don't know, sorry" or "can't help you". Long story short, there are other reasons why questions go unanswered in Help chat, but it's always blamed on other conversations regardless.
Some people don't care about staying on topic either way because they're just looking to advertise as much as people and repeat their messages across multiple channels. I've sent tells to people using Help chat like it was LFG asking them to please use LFG, their responses being "more people see it if I put it in both channels". Adding a General chat just means they'll spam their messages across all three instead. Unfortunately, this is just the nature of global chat channels anywhere on the internet. People will use them however they please unless there's some heavily enforced policing going on.