What are the benefits of adding db to context rather than importing it directly in the router?

import db from "../db";
export const createContext = async (opts: CreateNextContextOptions) => {
 
  return {
    db,
  };
};

import { protectedProcedure, router } from "../trpc";
import { eq } from "drizzle-orm";
import { db } from "../db";
import {
  clients,
} from "../schemas/clients.schema";

export default router({
  update: protectedProcedure
    .input(getAllSchema)
    .query(async ({ ctx, input }) => {
      const updatedClient = await db
    .update(clients)
    .set(input)
    .where(eq(clients.id, input.id))
    .returning();
    return updatedClient
    }),
})