Why get session again in `+layout.ts` for SvelteKit SSR?

import { PUBLIC_SUPABASE_ANON_KEY, PUBLIC_SUPABASE_URL } from "$env/static/public"
import type { Database } from "$lib/types/supabase"
import { createBrowserClient, isBrowser, parse } from "@supabase/ssr"
import type { LayoutLoad } from "./$types"

export const load: LayoutLoad = async ({ fetch, data, depends }) => {
    depends("supabase:auth")

    const supabase = createBrowserClient<Database>(PUBLIC_SUPABASE_URL, PUBLIC_SUPABASE_ANON_KEY, {
        global: {
            fetch
        },
        cookies: {
            get(key) {
                if (!isBrowser()) {
                    return JSON.stringify(data.session)
                }

                const cookie = parse(document.cookie)
                return cookie[key]
            }
        }
    })

    // // Isn't this redundant since the session is already provided by the server? Not making this call saves me a db interaction.
    // const {
    //     data: { session }
    // } = await supabase.auth.getSession()

    // The last load function has priority over all others, so I need to pass the server load data through the layout load data for the page to access it.
    return { supabase, session: data.session, posts: data.posts, message: data.message }
}

import { PUBLIC_SUPABASE_ANON_KEY, PUBLIC_SUPABASE_URL } from "$env/static/public"
import type { Database } from "$lib/types/supabase"
import { createBrowserClient, isBrowser, parse } from "@supabase/ssr"
import type { LayoutLoad } from "./$types"

export const load: LayoutLoad = async ({ fetch, data, depends }) => {
    depends("supabase:auth")

    const supabase = createBrowserClient<Database>(PUBLIC_SUPABASE_URL, PUBLIC_SUPABASE_ANON_KEY, {
        global: {
            fetch
        },
        cookies: {
            get(key) {
                if (!isBrowser()) {
                    return JSON.stringify(data.session)
                }

                const cookie = parse(document.cookie)
                return cookie[key]
            }
        }
    })

    // // Isn't this redundant since the session is already provided by the server? Not making this call saves me a db interaction.
    // const {
    //     data: { session }
    // } = await supabase.auth.getSession()

    // The last load function has priority over all others, so I need to pass the server load data through the layout load data for the page to access it.
    return { supabase, session: data.session, posts: data.posts, message: data.message }
}