You get cold air in either case - scoop sealed to the base plate/carb or not - but you pick up power by having a PROPERLY designed scoop sealed to the carb. A poor design can actually SUCK air OUT of the scoop.

On my car in C/SA back in the 70's going 115 or in SS/GA going 125 - hooking up the scoop to the air cleaner baseplate has always produced more power - shown in lower ET and higher MPH.

In fact John Baumman (Chrysler carb expert) jumped in my case when I ran slower at a Milan Test Day after a change in manifolds from the old factory six pack to the STR. When I took the hood off the car and he saw no baseplate he said "there is your problem". I had to "modify" that OE 69-1/2 baseplate with a hacksaw - added some sponge to the outer portion to seal it to the hood - and picked up a solid tenth and 1-1/2 mph. But don't believe any one person - do a base line test - if you have a scoop - attach a sealed base plate to the scoop and make a couple passes then take it off. See what happens. Don't give up because some people offer up invalid assumptions and opinions - TRY IT FOR YOURSELF.