For so many reasons....
I bought my Descent Mk1 before the Teric was even announced. When it was finally announced I looked at the specs and I was like "Meh". There were so many features of the Mk1 I was usually regularly that the Teric didn't have and it didn't offer me anything that I didn't already have with my Perdix AI. The only feature I wanted that the Teric had but the Mk1 didn't have was AI. For me, replacing the Mk1 with the Teric would be a major backward step (plus it was more expensive). If something happened to my Perdix AI, I'd buy another Perdix AI. The Teric doesn't interest me at all.
The Mk1 (and the Mk2 will be the same) is a full function GPS based sports watch. In fact, it is based on the very popular Fenix 5X which sold for around 2/3 of the prce of the Mk1. So in reality, if you were going to buy a Fenix 5X, you'd get a fully functional dive computer for only 50% more.
I use mine regularly for running. It has a built in heart rate monitor so I don't need to wear a chest strap. It tracks my pace, distance and even calories burned. I also use if for walking. I have used it for cycling and it gives me speed and cadence information from the bike. It can be used for swimming, too.
I have used it for bushwalking and then used the tracklog to geotag my photographs.
It is a all day/every day watch. It tracks my steps, flights of stairs, heart rate, sleep and stress.
It is a smart watch. I get all the notifications from my phone on the watch. My phone is permanently on mute. I never have to rely on sounds on my phone for notifications as my watch vibrates and I can read the notification on my watch. This also means I'm not disturbing people with my phone (and don't have to do anything while at the movies or the quiet carriage on the train. In fact, I now loathe all the noise other peoples phones make. LOL.
My phone can stay in my pocket and I will still know what notifications I'm getting, or if someone is calling me - and I can even see who is calling. In fact, my phone can be anywhere in the house, as long as it is in Bluetooth range, as I will get notifications.
That's just the non-diving features. For diving, it adds recording the entry and exit points for a dive using the built in GPS. This was something I was already doing somewhat manually or carrying a separate GPS device. I then geotag my photographs with the entry point for the dive plus the depth information from a dive computer. Now the entry and exit points are recorded automatically for me.
It can also measure heart rate during the dive - assuming your exposure suit allows the watch to be worn directly on a bare wrist. I'be done this a few times. It was interesting but not something I'd find useful enough to compromise my wetsuit or drysuit. Note that there is a chest HRM that can be used if someone wanted to do that.
Now, I'm not saying it is perfect. There are a few features that could be improved if Garmin could be arsed. But for me, and a lot of people, this is a better device that the Teric.
My fear with the Mk2 is that it's going to be in the MARQ range which will make it significantly more expensive.
