You can easily see conversations that took place when you're offline and you don't have to scroll through add-on announcements general chat or anything else to view it.

The different channels are incredibly helpful, I just set one up for a guild bank to post everything that's in there and allow people to request it, a somewhat decent middle ground to having a designated guild bank like retail.

One less add-on I don't have to worry about updating properly. It literally just works.

However for classic era I kind of get it. I really don't think any changes should ever be made to those servers but for season of discovery and other "classic-like" servers it's just an improvement.