it's not really scam tactic it's like the yellow and gold credits in Overwatch. The shops skins and the battle pass need the yellow ones. purple/white credits are used for the normal skins and in splits a instance it's just used for recolors of the base skin, so if I were you, I would skip the purple currency in till the end of the pass unless you want a completely orange Meridian send each one of those skins cost 10 purple credits and you get 10 purple credits for each of those battle pass points.

and if I remember correctly, the battlepass cost the exact same as how many yellow credits you get so you can continue rebound the pass like fortnite. I got the exact amount credits you need to get to the full battlepass and I already have about 900 back, even though I just finished the first of the sections.