Other than "exploding" organs, what other affects do the pressure points have?
they mind-wipe, mind-manipulate, mind-control, they can degrade your muscles to below-average-human levels, make you blind, remove your bones, paralyse you completely, cause immense pain, cause death directly, turn you to dust and remove your soul (unclear whether it's a pressure point technique or not, but alas).
This is just the pressure point stuff, he also has stuff like Soryu Tenha, which is powernull that equalizes stats, Gento vaporizes the opponent's cells, Seito Gekken generates a flame that's impossible to extinguish and negates regeneration and probably some other stuff.
And they able to revert themselves back for as long as necessary
The fact that they can turn themselves back from a very specific condition (which stretches the meaning of "resistance to biological manipulation" to begin with, since they are REALLY just resisting transformation and even if we granted it the status of biological manipulation, it would really just fall under "body control" and "shape change", not "cell manipulation") doesn't mean that they can freely control each hormone in their body.
And they able to revert themselves back for as long as necessary. Saitama himself is able to manipulate his subatomic particles so hormone alteration means little
I have no idea what you're talking about, if it's about the radiation thing, are we gonna say that Toki is "able to manipulate his sub-atomic particles" because he resisted a dose of radiation that was 50 billion times higher than the dosage that would instantly kill a normal human and gamma radiations effect matter on a subatomic level (electrons)?