I wear one, Freestyle Libre 2, which is not the best out there but good enough IMO.
I think it really depends on what your diagnoses are, what other meds you take and your GLP-1 dose.
If you are T1D or T2D and need insulin, a CGM is a no brainer.
If you are taking a high dose (10mg +) or have tried a standard finger prick test a few times and consistently get low readings, then I'd consider one.
I'm prediabetic, my A1C was 5.7 before starting tirz. I take a low dose of metformin (500mg extended release) a day, and my dr wanted me to keep taking that, in addition to tirz.
I have a finger prick blood glucose meter and honestly, I think that's more than enough. I used to track my fasting BG daily, or at least before the shot and 1-2 days after. It's easy to check your BG this way If you suspect a low BG and eat something. You really don't need a CGM to tell you that, feels like an overkill.
Now, let me tell you why I went back to the CGM this month. I have insomnia: I can fall asleep without any issues, but most days I wake up in the middle of the night (anything from 2:30 to 4:30-5:00) and can't go back to sleep, no matter what I do. Normal sleep aids don't help me at all. So I suspected that I might have low BG during the night and that was triggering a cortisol spike and waking me up. So I went ahead and put my CGM back to see what's going on. I'm at a low dose (2.5mg) so I wasn't really thinking it was a hypo event, but.. you never know. I can see that my bg consistently decreases for 1-2 days after the shot. The lowest is 82. I did have a few 70s but seemed more random. So no, I'm not waking up due to hypo events. Maybe you are! So it's not a bad thing to verify if this is your case.
So my two cents: check with a finger prick a couple times. If you really do see a pattern of hypo, then ask your dr for a prescription. Unless you are T1D/T2D, insurance might not cover you. You can use GoodRx for a discount anyway. I paid $82 a few weeks ago for 2 sensors (1 month) without insurance, just the other discount.
Side note: I agree with
@Dee X that is cool to see how your glucose fluctuates. I think it's an overkill to try to tweak carb load, the order of meals, etc based on this, since GLPs really do the heavy lifting for you. But it's fun to see anyway. You get to learn how your body reacts to certain foods, exercise, etc. I did a few experiments before using Tirz and it was illuminating. Back then, it also helped me prove to my endocrinologist that I had insulin resistance.