Like, if you decide to do your backend in rust or python you can choose async or synchronous approaches - but Node locks you into async. I'm not a node developer so I can't sing the praises of what you get, but being locked into JavaScript's process model, VM, and type system is certainly a downside (for which you get the whole JS world). It's another example of...if you are architecting your service and you pick this you are picking some built in trade-offs.