There's no notion of uptime, provisioning or managing Web sites when using Web sites; but the operators of the Web site certainly have to tackle such things.
Likewise, I'm sure the operators of AWS lambda are very much concerned about such things, even if the users aren't.
In that sense, wordpress.com is "serverless".
Hosted WordPress is SaaS but not FaaS.
In essence, it's a return to the "cgi-bin" model of scripting, where you write a script that only runs for the lifetime of one request, and then a web server will spin it up to respond to a relevant request and it'll terminate at the end of that request.
The only differences in the modern instantiation of the concept, are that:
1. the "cgi-bin" directory is a mounted object store, common to an entire cluster; and
2. there's some fancy preloading logic that lets Lambda functions stay "hot" between calls to them, so that they can run very quickly. (Sort of like Phusion Passenger does for Ruby code, except with enough isolation to make it safe for multitenant environments. Heroku's old Alpine stack might be a better comparison.)
The other lambda fires on a cron job https://github.com/serverless/post-scheduler#cron-job-archit...