good point via Twitter:

The current docs confused me a bit as a Next.js user by comparing load to getServerSideProps/getStaticProps, while it’s more like getInitialProps in the way that it exposes everything to the client.

They currently say this, which isn't totally accurate:

load is the SvelteKit equivalent of getStaticProps or getServerSideProps in Next.js or asyncData in Nuxt.js.