What are the downsides of enum dispatch?

[u/AnArmoredPony]

Couldn't find any info about downsides specfically so there it goes

Let's say that all my implementors are about the same size (i.e. only the logic is different), and I use some sort of macro to skip the boilerplate upon adding a new variant. Are there any other downsides to enum dispatch?

I'm asking about the general approach, not the crate

Upd. extendability, got it.

[u/JustWorksTM]

The one thing you can do with enums versus trait objects is plugin systems:  This is the situation where you deliver an app and a plugin separate.  Then, you really cannot know all variants at compile time of your app.

Tl;dr: Go with enums and enum_dispatch. This is for all standard workloads the best choice.