[gwd]

3. Discover you can't join a lot of channels because you're not registered; or worse, that your messages sent to the channel are silently discarded

And you still have the problem that if you're in the wrong time zone and happen to close the window, you may miss responses.

There are advantages to having high barriers to entry for a community; Ham radio is essentially a global chat room with an entrance exam, for instance. But there are costs too.

[jankovicsandras]

Your point 3. is true generally, but - as I understand - parent wanted to operate a customer support channel and dismissed IRC. In this case: just don't lock your channel for Guests. Timezones affect other platforms, but an IRC bot might help customers when admins sleep. But I'm not sure IRC is best for this use case (e.g. forums, wiki are probably better), but "high barrier of entry" is arguable.