it boils down to financials.
for me personally, i buy what my heart desires bc if i dont, then ill constantly wonder and eventually buy it anyways. kinda ocd. this is of course, after ample time having passed so i can save money to afford it.
some people like having lots of less expensive/middle of the road guns. some like both higher and middle ranging guns.
handguards can be compared just like any other part of this modular rifle. again, it's designed as a package to make performance improvements.
geissele trigger vs mil spec, troy buis vs magpul, surefire lights vs inforce, surefire brake vs yhm brake, miad grip vs milspec grip... do they serve the same purpose? sure, but u cant tell the industry leaders that it wont make a difference besides splitting hair.
even if u may not agree up to this point, splitting hair makes a difference. ask the 3 gunners or a situation when u need o send 30 rounds downrange and barrel control is essential