It looks to me like Garmin should have involved some actual divers in their design process. At least one diver that has been around for at least a little while. The Mk2i brings absolutely nothing new to the table, from a diver perspective, but Garmin doesn't seem to get that. Or, maybe they just want divers to not realize that...
Liquivision had "sonar" technology for their air integration transmitters. They even had (if I recall correctly) a module that you could mount on a boat, so that the boat crew could monitor the tank pressure of up to 10 divers in the water. I actually wonder if Garmin actually picked up the Liquivision tech to use as some basis for the Mk2i.
I think Liquivision also had a module that could be used as a boat locator. I.e. a sonar beacon that you could hang off the boat into the water, and Liquivision dive computers could orient on it in the water, so that you could find your way back to the boat, even if you were lost and/or in low viz.
And guess what? *gasp* Liquivision failed as a dive computer manufacturer. Even with all that superior tech. I have not been diving that long, so my personal anecdotes don't really mean much. But, I have only ever seen one of those Liquivision computers out in the wild - and that was one that a buddy of mine had and was trying to sell (after he got a Shearwater). I am highly skeptical that Liquivision sold very many of those (with AI), at all.
As for instructors jumping on a bandwagon for using these Garmins because of the 30' range... First, is an instructor going to buy a Descent Mk2i for him or herself, and then require all their students to buy at least a Garmin transmitter? No. Is an instructor (or shop) going to buy a fleet of the transmitters to put on rental reg sets, so that all their students can use them? Color me highly skeptical. HIGHLY skeptical. As in, VERY few will do that (my prediction).
And all of that really only applies to teaching Open Water. Once a student moves on to Continuing Education, they may still use rental gear. But, you hope they're going to buy their own gear and you certainly can't make them buy Garmin. And it's hard to imagine many shops/instructors insisting that ConEd students install a shop-provided transmitter on their personal reg, or requiring the student to use a shop reg set.
So, yeah. I don't see this feature of monitoring other divers' transmitters getting used much at all by instructors. Personally, I wouldn't really use it, even if I had it. I think it is important for my students to get in the habit of checking their own tank pressure. So, when I want to check what they have, I specifically want to ask them to tell me, not just look at my own computer and see what they have. I want them to have to look at their gauge, interpret it, and tell me what they have.
I guess a buddy pair/team might value that feature. Maybe a husband who wants to keep an eye on his wife's pressure (or vice versa). Or a parent who wants to keep an eye on their kid's pressure. But, I'd tell them the same thing I just said. Instead of monitoring behind their back, ask them. Make them check their gauge and tell you.
I said when the OG Descent came out that if they made an AI version that would work with PPS transmitters, I would buy one. I still feel that way - but with the caveat now that Garmin would also have to unhandicap the Subsurface developers and allow them to add support to Subsurface to download via Bluetooth. This is 2020. Being required to use a cable to download sucks. And, right now, you can only download directly from a Descent to Subsurface via USB cable. That is just Garmin trying to force people to keep it in their ecosystem. Even if they added support for PPS transmitters, that would still keep me away.