they are called micro grafts, not plugs. Plugs are available for anyone who does not do their research, and look like dolls hair.
Some people will continue to lose enough hair to leave a weird looking hair island. This is particularly true of people who just use propecia instead of the big 4.
The sides do have 5ar2, but just half as much as the hairs that are balding, and half as many androgen receptors. Head hair makes more 5ar2 and more androgen receptors as you get older, and may stay at a certain level for a while or progress faster, just depending on your genetics. If you look at the side hair of old men, it is thinner, even down by the neck. It just does not go completely away like the top does. Some old men are dense even on top. Propecia will help preserve your sides. And since folligen is so cheap, I apply that to my sides as well. It dries fast.
If you get big strip scars up high and go bald there later, you will have a scared look. If you get thin scars down low and keep most of your hair, you will not look bad.
If all your grafts are in your hairline and the rest of your head receeds, just shave your head. the graft roots will still frame your face. Again, you need a Doctor who can give you thin scars in back. And FUE probably is visible since no Doctor has close up pic even of BHT donor sites 3 months post op. I see no reason why they would not post those everywhere if they actually had any skill. And the back of the head donor sites will have even bigger scars. I'd rather have a thin line, which has much smaller surface area.