Gleam, much like any language which primarily targets BEAM, is slower by an order of magnitude or two when compared to F#.

The appeal is the runtime model. I can’t readily verify if BEAM languages are meaningfully slower or really slower at all but let’s take the premise for the sake of argument.

Even if is slower, the runtime model is incredibly resilient and it’s cheap to scale up and down, easy to hot update, and generally does asynchronous work extremely well across a lot of different processes.

F# has really good async ergonomics but it doesn’t have the same task/processing flexibility and Websockets are kind of a pain compared to elixir or even erlang

For most of the workloads you’re putting on the BEAM, they are IO bound and this is not of any consequence