That's exactly it. Without an eGPU, the MBP's fans get VERY loud if you push it, especially if you push the built-in discrete GPU.
With a 5700 XT eGPU, my 16" acts like nothing is happening while putting out performance to shame any laptop out there. Fans at minimum, feels as cool as ever, no noise. As for the 5700 XT itself, it has 3 fans that are very quiet, and I can't hear them even while running games - in 6K resolution, no less.
With a Pro Display XDR in addition to the eGPU, my MBP turned into a "baby Mac Pro", including the upgradability part.