To me, serverless means that I as the developer don't have to do ongoing server maintenance work. A 4 Euro/month setup sounds great, until you find out that you never enabled log rotation and filled up the disk space, or your certificate refresh was improperly configured and now you don't have SSL, or your site gets popular for a day and the site slows to a crawl unless you add an instance.
The dream of serverless is that I can deploy code in a “set it and forget it” manner. Stuff can still break at the application layer, but should work the same at the infrastructure layer in a year as they do today, and auto-scaling happens automatically.