FWIW sudocream is rubbish as an anti-chaff cream. You'd be much better with either Assos chamois cream or Udderly Smooth.
FWIW it doesn't taste very nice either... but then you're not meant to eat it!
To be fair to sudocrem, it's not a chamois cream like assos or udderly etc. It's an 'antiseptic healing cream' that cyclists happen to press gang into service. I guess because it's cheap and plentiful. For many cyclists, myself included, it does the job well. If you look at the container, it says nothing about being an anti-chafing cream so I guess that if chafing is your problem that you're best served looking elsewhere. Like you say, maybe at the more expensive (and designed for) products.
Coincidently, I have just come in from a 100km ride (well, 103.4 to be precise) and for the first time ever I used Udderly Smooth.... and my ring piece is stinging like a be-itch! But I'm nit blaming Udderly just yet. It could be my fault. I over dressed, misgauging how cold it was going to be. It was an afternoon for bib-shorts and leg warmers rather than winter tights. My fault... but I reckon sudocrem would have prevented the rash.
But there you go. We're all different. Butt cream, like saddles, is a personal thing. I know I run hot and tend to get sweaty, so I need a barrier cream more than I need a minty tingly feel below. Each to their own.