Just commit, no matter the response. Adding /s is akin to explaining a joke after you tell it. If someone doesn’t understand or pick up on the sarcasm, it’s not your responsibility to spell it out for them. You add /s because you don’t want to be held accountable.
Nobody needs to explain sarcasm, but sometimes you need to indicate satire.
Or, I just want to imply that you are a /super /special person. IMHO, it’s just good to give appropriate context to someone /s.