Why would you run something in a single location if you can run it everywhere for the same price though? It's not like Lambda is cheaper for being centralized.
Isolating failure domains and complying with data residency requirements are a couple reasons. Also, global reach usually means global blast radius if you screw something up.
For the specific use case you tested workers on the edge absolutely make more sense than lambda, but I think the headline is a bit click-baity.
If your function is IO heavy and your datastore isn’t globalized (as most aren’t, save Spanner and its ilk), you may prefer your function running in the same region as your data to minimize DB latency and transfer cost.
At least you acknowledge that it's a bit silly to use a global benchmark to compare a global service with an intentionally-regionalized service.