Other strategies can be just as viable, and you can even pull off a win by just being friends and playing nice
You are happy enough playing a fairly rubbish card just to have a good cheap sac outlet
A close second is Hymn to Tourach, but both cards discarded are random and is less useful for competitive play
This Planeswalker has a starting loyalty of 3 and cost 3 green and 2 generic, for a total of 5 mana and has the following abilities attached to it: +1: Create a 3/3 green Beast creature token
The only real times I would want to splash other non-red colours is when I didn't get enough playables in green and needed to make up numbers
Rev, Tithe Extractor, Gonti, Night Minister and Shirei, Shizos Caretaker all love this one, but I especially like it in Gix, Yawgmoth Praetor