The pressure point is there because the threaded joint of barrel and receiver is not reliably rigid. The pressure point pre-stresses the barrel. It tends to reduce fliers.
I think "reliably" is the key word, you'd expect a properly fitted and assembled barrel/receiver to be plenty rigid. Past that I think the pre-stressing against the stock provides dampening to somewhat suppress (statistical
) variations in barrel vibration which can come from any number of things. May be helpful, maybe not, depending. Since manufactures build and test fire gazillions of rifles I suspect it helps more than not for mass produced rifles.
So I think we're saying essentially the same thing in different ways.
(Just felt compelled to stick statistics into the mix.
)
