Optional
Well remember SIP can be turned off simply enough, troublesome Kext's removed, and either left off, or re-enabled, no biggie for most, if you need to, but for many, they will just leave it all 'as is'
for me, I *always* remove iTunes, messages, all that photo, maps, social media and cloud crap, and the rest of the included shovl-ware.. but admittedly, i'm not exactly a regular type of user however..