LeetCode is transferable skill, any time you spend practising those types of problems will scale to all interviews for all companies you are going to be doing in that interview batch (and perhaps even years into the future). It also serves as a good review of CS fundamentals which you may have forgotten since college or never learned in the first place.

Nothing like that can be said about a take home-assignment asking you to implement boring app with a backend, frontend and a suite of tests over the course of a day to an entire weekend.

Leetcode is like O(1) time work (admittedly with a large constant) that doesn't generate additional work for every company you are applying to. Take home assignments are O(n) time work where you have a bunch of crap to do for every company.