So I’m someone who actually designs and deploys speakers in large scale applications like arenas and performance halls. There is some truth to making all of the frequencies arrive at the same time based on your listening spot. However the “peak of an average waveform” is bullshit. The reason why time alignment is a thing is because of 2 reasons.

1. It takes time for the diaphragm that is moving the air that produces sound to move. A smaller diaphragm that produces higher frequencies will move sooner than a larger diaphragm that produces lower frequencies meaning the higher frequencies will arrive to your ear before the lower frequencies.
2. the speed of sound is not a constant. It varies with temperature, humidity, and atmospheric pressure. Unless you have a fully pressurized climate controlled space the speed of sound will vary, meaning the time alignment will vary.

Is any of this important? No. Sound (any wave really) will merge with other frequencies and produce a unified wave as long as the drivers are close enough together. So as long as the distance between the tweeter and the woofer is within half of the wavelength of the crossover frequency, it literally does not matter. The crossover’s between the tweeter’s and the woofer’s in most speakers are typically within 800-2.4khz, or 17”-5.6” (43cm-14cm) in wavelength. As long as your drivers are within that distance of each other the sound will converge.

And if it wasn’t, we can delay the electrical signal in the amplifier to make it all line up!!

As someone who designs audio equipment, I hate audiophiles, they make a mockery of my profession.