Why 2* are still relevant (even if they don't really matter)
2* are still relevant for a couple reasons ...
1) if you max milestones in summoner trials you get 5-6 prems, a ton of BC , units, and gold... and it only takes 40 or so matches to achieve (for me about 90 min of game time).
2) Once you max all PHC 2* (sig 99) you get 3* champs twice as fast, which snowballs into 4 and 5* champs over time.