Ports are not just holes....A ported box is carefully designed with the Thiel-Small parameters of the woofer according to scientific principles. It has a specific diameter and lenght to resonate with the box at the correct frequency depending on the woofer.

think of a woofer and box as the suspension of a car...You cannot just add any old springs and shockabsorbers and expect race car performance. Too weak and you bottom out and wallow all over bumps...To stiff and things break.

I "general" sealed boxes are smaller and easier to build for good sound quality. Ported boxes are larger and can go to lower frequencies...But neede greater care to design and build properly....Those are the basics and I am sure that experienced box builders will come up will all sorts of other details and exceptions...

best bet for a novice is to go to the website of you subwoofer and get the sealed or ported box recommendations.