It’s the perfect anti-chaser mechanism, and allows you to put much more pressure on the Fireteam so they can’t complete the mission as quickly. I don’t use it on every single build but it is the one perk that I am most comfortable with as it allows for much better pressure like I said and it really helps when you have people like Gesp chasing your ass down. Some missions for Fireteam can be done in 2-3 minutes, due to the medic perk alone I have been able to put enough pressure on a premade team when they had the camera mission on Derailed so that the match went on at least twice as long before the last 2 players called the chopper and I was able to prevent them from escaping. It is really a great perk but it’s truly down to you whether you use it or not. I don’t use it on my Elder Stalker because I prefer the combination of Dithered lens, Down range and Adrenal boost for a ranged build, of which if you’re playing it right shouldn’t really require medic because you’ll be playing so far away and cautiously that you shouldn’t take much damage throughout the game and can heal comfortably away from the Fireteam with minimal threat of chasing.
Instead of medic you could just use adrenal boost and rely on pigs a lot more but the main problem with pigs, especially for me, is that premade teams like to cock block me from getting pigs every time by literally just watching the pigs and never leaving them alone until either they call chopper or I use another healing kit. The pig spawns are also very predictable and almost always spawn close to the Fireteam.
Using medkits are a more safe option anyway, but with medic they have even more utility.