You get a higher multiplier on campaign for the noob combo.
"EMP" – Remember the “noob combo” from Halo 2? This was the term coined to refer to using a plasma pistol overcharge blast to drop someone’s shield and then immediately following up with a BR headshot for instant win. Use can use this technique against the Covenant throughout the campaign and it’s particularly useful against Brute adversaries. If you hit an enemy with a charged plasma bolt and then get the finishing shot off within 3 seconds, you’ll earn a 1.25x point bonus.