Kompu or complete gacha refers to a practice of compounding multiple randomized prizes into powerful sets (which can be extremely hard to complete). For example, imagine an armor set that comprises of 6 pieces (3 common, 2 rare, and 1 legendary -with an incredibly small drop chance). Thanks to a set bonus (for having all 6 pieces), the power of a complete set is much greater than the sum of its individual parts.
By diminishing the value of base components and making the ever-elusive grand prize the ultimate goal of spending money, the model has turned an already popular gacha model into something even more lucrative, but not for long...