I'm not sure which events you're referring to, Chic, but our experiences have clearly been very different with regard to events.
There's always multiple takes on everything, I guess. After doing over 30 events of different sizes over several years, I can't agree at all that mixed events are always better for home and garden creators. I think it depends completely on which event it is as to whether it is better or worse—many/most of my experiences with "mixed" events really just add up to home and garden creators given (1) too small a booth to do anything with, (2) a low prim allowance that hinders any substantial display, and/or (3) shoving us off to a demo area that most shoppers won't visit.
I've been in several only H&G events too, in the last couple years. Two of them closed for reasons that had nothing to do with whether they were successful or a great shopping experience for designers and shoppers; it was all a big mess of drama for one of them (Illuminate), and a complex mix of reasons for the other (Blueprint). The third one, the Boardwalk Event, is going strong and is already full with over 50 designers for the 5th round in July. (Full disclosure: I'm part of the organizing team for Boardwalk.)
What's more, some H&G designers will find that an event does very well for them while others—even with similar styles/stores—might find that the same round of the same event doesn't meet expectations. My take-away from all of it is: regardless of the size or prominence of the event, and regardless of whether it is "mixed" or an all H&G event, there's no way to accurately conclude that one sort of event setup works better/best for H&G designers across the board. If there were, you can bet that, as both an H&G designer and an event organizer, THAT would be the kind of event I would be striving to put together.