I think it's an interesting point of view.  My guess is they're coming from the bigger picture of how decentralized systems without a middleman are useful.  Since Bitcoin cuts out the middleman, theres no one to go ask for your money back - which also means you don't have to pay fees for chargeback protection like with credit cards and stuff.  Even if you don't get an advantage all the time, having a system that's predictable can be valuable in itself.  It simplifies everything when users know upfront that transactions cant be changed later and 

overall I'd say the pros of Bitcoin being irreversible are 1) no fees for chargebacks 2) fits with the decentralized model and 3) makes the system straightforward because you always know where you stand.  But I'm just speculating based on what I know about crypto and payments.  Definitely an interesting perspective from certain users.