Dunno why peeps call grenade launchers and powerful combos "noob". It's a good strategy, then use it.
No one is saying it makes you a noob. It comes from the old Halo days. The old
"Noob Toob" was the Halo 2 rocket launcher, because it had lock-on for everything. Which sucked, and basically took all the skill out of using it. In Reach, the Rocket Launcher only locks onto airborne vehicles, and even then, you can evade them if you pilot them well.
And the
"Noob Combo" was referred to that not because it
made you a noob, but because it was soooo easy to
kill them with it. Run around with the Plasma Pistol charged up, blast someone to drop their shields, quickly switch to the BR, and boom, headshot and done. Now there are a couple ways to pull this off. Either an
Overcharge shot from the Plasma Pistol, or a
Delay Shot from the Grenade Launcher will EMP your target, leaving them open to a quick and easy one-shot headshot.
But again, as I said earlier, getting your hands on a headshot-capable weapon is not that easy in Reach campaign, so you have to be very efficient with your ammo usage to keep it up.