Yes, every process a person/language/company/country/etc.. adopts has a cost. It's not free. The question is if being forced to always deal with errors is worth the cost of always dealing with errors.
I think it is. I will gladly trade a couple of hours of extra error handling code every week in exchange for no pager duty alarms on the weekend.
I read it as "let's stop pretending we are wizardy wizards and can do things right way in 100% cases and let the language to enforce us to handle errors, producing better result for average Joe SR SWE".
Am I right with my readings (i'm not a dev guy at all)?