This is an expensive little device, and it's not for everybody, so I'll try to help you decide whether you want or need it in this review. Here's a little background about me: I'm in my mid to late 30s, and I've been cooking in a variety of ways for the last 20+ years. I got interested in cooking in my teens, and I've learned a lot since then. That said, I'm no professional, just a considerably above average home chef. I also love all different types of meat, from red meats (beef and lamb mostly) and pork to poultry and fish/seafood. In my years of cooking, I went from getting down the basics to trying to fine-tune my craft and just get as good as possible at the things I'd already learned rather than trying to add many new tricks to my repertoire. One of the ways, I feel that it's possible to greatly fine tune your cooking is to get the temps/doneness of different things just right. To a point, I feel comfortable cooking different pieces of red meat to the right doneness without a thermometer (the touch test is pretty accurate most of the time), and in general I have enough experience with my different devices to know when a hunk of chicken is done but still moist in the air fryer. But a thermometer like this can offer an extra level of precision, especially when roasting larger (but perhaps not humongous) items.
So, this thing sets up with an app on the phone. The range of the thermometer itself is fairly limited, but if you leave its little thermometer holder nearby, it extends the range significantly. There are some potential concerns with the app, such as location tracking, so if that bothers you, you may want to steer clear. The app is pretty convenient, though, as it warns you immediately when the meat you're cooking reaches the desired temp.
The size of the thermometer is good for most food types. If you have a massive turkey or rib roast, you may not get quite the depth you want, so it would make sense to set the desired temp slightly higher than you want the internal temp at the deepest point in the meat, but for most types of steak or hunks of chicken, it could work. For smaller items, it works fairly well, but you should be aware that for it to function correctly, the entire metal part should be inserted into the meat. I love cooking lamb **** chops, and I've struggled to get the metal fully inserted as you can see in the attached images. Once I figured out an angle that was about right, it worked out, but I couldn't really get it inserted to hit the furthest point inside, closest to the bone. For medium pieces of meat, it's fine, and if you're cooking multiple, you can come up with roughly uniform results if the pieces are similarly thick or you adjust timing for thickness differences.
Ultimately, if you're doing a pretty good job getting food cooked to the right temps already with either nothing or a non leave-in meat thermometer, you probably don't need this, but just because you don't need it doesn't mean you shouldn't have it. It might be an extra level of convenience and precision that you'll appreciate, even if it's not a total game changer, which is how I'd describe it for myself. If you love cooking but you struggle to get temps right, it could be a game changer.