claymores are for prepared ambushes. if you can set up claymores in advance of where the enemy is going to go you can get a lot more of them as they will be caught completly off guard. you have to throw a grenade and time it right, introducing risk of detection, risk of poor throw, risk of poor timing. claymore mitigates all those problems, when you have good intelligence and time.
grenades are for assaulting well fortified positions with minimal risk to the user. you can throw a grenade into a room, trench, or bunker and be reasonably sure anything that was in that room is now dead.
grenades are more useful from a general purpose perspective but for the niche the claymore is designed to fill it more than justifies its carry weight.
so if you are assulting a fortress a claymore isnt going to do very much for you but if you are preparing an ambush or doing some deep raids guerrila stuff a claymore is a great tool
