I noticed that a very simple script of mine (just returning a query from a JSON file) was much slower than expected.
It turns out that just require('alfy') adds about 120ms to a script's execution time.

Since I only used alfy for outputs I replaced

const alfy = require('alfy');

with

const alfy = {
    output: (items) => {
        console.log(JSON.stringify({items}, null, '\t'));
    }
}

Now Alfred feels snappy again. :-)