Gleam doesn't have macros, which many Elixir libraries (such as Phoenix and Ecto) uses to great effect.

Gleam for example has issues with verbosity of decoding/encoding json whereas in Rust you derive serde and in Elixir it's just a function call away.

Elixir has a more mature ecosystem. While you can for example use Phoenix with Gleam (or some other Gleam framework) the experience just isn't the same.

The big draw with Gleam over Elixir is the typing (where Elixir is now closing the gap) and being able to compile to JavaScript (which is also what Hologram is doing for Elixir).

I prefer Gleam's typing system and the Rust-like syntax, but for now I feel Elixir is the better choice for all my web dev projects.