I learned my lesson on extra fuel early on in a commuter turboprop on a double-diversion day. Had I not carried the extra fuel I'd have had to land a Cat1 aircraft at STN in RVR 150. (40hrs on type)
From then on I continued to take what I felt was needed and when (later) employers sought justifcation I just used to write "Captaincy" on the flight report.It was never challenged.
fwiw I never (in 5 UK airlines) encountered jobsworth ex-mil people in Flt Ops trying to make a point (Chief Pilots, quite another matter). These min-fuel diktats don't usually if ever originate in Flt Ops, they are the bastard spawn of the grey-faced accountants that have so wrecked the industry.