3 stars in cavalier crystals

What is the logic in putting two tiers (3* and 4*) of unusable champs into the cavalier crystal? At least with 4 stars you can get 5* shards and that can help you get more 5* crystals that you can then use those champs in act 6. but 3*s will only help you get 4*s that you can’t use in act 6 and at least 4*s are usable in other hard content like epic and master difficulties of Event quests unlike 3*s that are pretty much useless at this level. I think the team seriously needs to look into removing 3*s or at least severely lower the option of obtaining them and put more emphasis on the 4 and 5*s.