Well, chalk it up to flattery and a bit of competition.
Actually, I think that the Boom drum machine takes a bit from Guru—the pattern sequencing and the midi notes that can trigger the patterns.
I've been a PT user for a couple years. In general the AIR plug-ins and instruments are nice, they look great, and they function well...to a degree. When you buy Pro Tools, all your bases are covered, to begin with. You have a sampler, a rompler, a couple synths, a drum machine, etc. So, if you're a newbie buying into ProTools, you have a complete beginning palette to work with...very good, that's the way it needs to be in the world of marketing a modern DAW.
But, when you want to do any kind of "serious" work...and by serious I mean putting in more than a few hours a week... the AIR plugs are not the place to be.
The first, and painfully obvious thing about them is that they're RTAS only, and connected to Pro Tools. Pro Tools 8 has been really buggy for a lot of people, and Pro Tools in general is at a cross-roads—if they don't figure out how to release a fully native and fully featured product in the next release, they're probably going to lose their entire single-producer/musician user base, and go back to being mainly Pro Studio audio app. I know I keep an up to date version of Cubase, and any time Pro Tools is a limitation or a problem (track count, lack of off-line bounce, etc.) I go back to working in Cubase. So I CAN'T invest much money, or more importantly TIME, with plug-ins or instruments that are RTAS only. If you look on the PT forums, you'll see that an amazing amount of PTLE users are also running Reaper along-side PT, or have even migrated to Reaper.
The second thing is, once you really examine an AIR plug, and you do a little research, you can usually find something that's much better that does the same thing. So, I start fooling around with PT's Boom drum machine...and thought it was pretty cool. I liked the pattern triggering. But, as soon as I go to use it in a mix, I find that it doesn't have separate outs...stereo out only. so, I could bounce to audio (insane), but, PT doesn't even have offline bounce...grr. So I started looking around, found Guru, tried the demo, and realized Guru is about 20 times as powerful as Boom, and actually easier and faster to use! I imagine it would be somewhat the same thing comparing Transfuser to Guru—I'll bet Guru does it better, though I haven't actually tried Transfuser.
Another example is The PT "Hybrid" synth. Really neat piece. I love the sequencers that you can assign to modulate filters, panning, and all sorts of note properties. Problem was, when I tried to use it in a mix, just to find a bass sound that I liked, none of the sounds really held up. Nothing really seemed solid. So ... I started looking around and found Alchemy. Who-hoo, now I see where Hybrid may have gotten some its feature set from. Only Alchemy is 20 times as powerful as Hybrid, AND sounds great, AND is multi-format--VST, AU, RTAS. So Why would I waste my time with Hybrid? Synths take a lot of time to learn to use well. I've gotta spend my time wisely.
So I wouldn't worry about what Digi, or AIR does. In fact, Fxpansion just sold Guru to me because Digi included Boom in PT8