This is a slightly about face way of looking at it but hear me out...
I am the kind of user that embraces everything new as soon as it is possible, so by default I would always tend to want a plugin version of the Fractalverse. I have Helix Native, midi controllers, every kind of plugin you can possibly think of and yet... I am actually really glad that the FM9 wasn't available as a "plugin" when I decided to take a punt on buying one.
If the FM9 plugin had been an option at say 25% of the price of the hardware I would definitely have gone for that with the attitude "well I'm basically getting the same thing at 25% of the price" (I'd have kidded myself this was the case even though I would have known deep down that it wasn't ever going to be the same).
Playing through the FM9 is sooo much better than playing through plugins, like almost ineffably superior, and plugins are really only something I use as a fallback when the FM9 just can't quite do what I want (which is not very often), or for re-amping. For e.g. I will route through plugins for additional psychedelic or ambient effects where the difference of 10-15ms latency isn't killing me.
Don't get me wrong, STL, Helix, Guitar Rig etc. they are all great at what they do but coming from real World kit to digital over the years I can 100% still feel the huge difference when playing through the PC with plugins. The FM9 is not an Amp and Cab but it's a lot closer than a PC plus plugins in terms of response especially, for me at least.
The other aspect is hardware reliability. I've been working with computers for years, and the best shot you'll ever have at making a reliable architecture is to design and assemble the hardware configuration yourself. But that's almost a secondary point in this debate I suppose. As I said at the beginning I'm really glad that I got to discover just how good the Fractal units are compared with just about every other digital offering I've ever tried, and that wouldn't have happened if a plugin had been an option. That wouldn't be true for everyone, but it probably would for a fair few. So I guess, be careful what you wish for... if everything moves into PC World, we'll all miss out on these amazing pieces of hardware.