The Kick Port can be useful in extending some frequencies otherwise lacking in some drums or tuning choices. It can also over extend frequencies already present in sufficient balance without it, so it's a personal choice thing, just like head selection, depth, diameter, etc. It's not a "cure all", & nor is any other extra you can buy, but it is a valid solution choice.
I find the Kick Port interesting, because it goes some way towards demonstrating how a shell affects sound. A drum shell's shape & resonance profile has a profound affect on resultant sound, despite what the naysayers preach. I often use the analogy of a speaker. The cone of the speaker being the heads, & the cabinet of the speaker being the shell. Some reflex (forward facing/open fronted) bass speaker enclosures use a port or ports similar to the Kick Port. I won't go into the science, but it wouldn't surprise me to hear the Kick Port design was lifted from speaker cabinet designs. Funny, how the same people that claim a drum shell's resonance has little do do with shaping the resultant sound, wouldn't claim the same applies to a speaker enclosure.