How about this?

The concern of players - removal of plat blessings and useless vanities taking over Day 5 rewards;
The concern of STS - giving away too much plat, being taken advantage, losing money

Therefore, how about day 5 rewards include a 5 or 10 plat DISCOUNT on one plat purchase for the next 24 hours?
Therefore, the player gets 'plat' in terms of a discount on an item of his/her choice, and STS actually gets more sales by encouraging players to buy plat items (even with the small discount).