Thanks as always :) You didn't get the 150 dust from leaving the event, you got them from killing the "boss", you can see them drop as you kill it ;) (@ 11:47)
It seems that the shop will be extended with the release of next month's patch with new materials to buy. That said, the way they communicated around it is just plain bad and confusing. Though we are still missing honing books (which is particular since they want to help the players progress their roster faster) and hopefully the missing usual legendary select pack will arrive with the extended shop. I like that there is now green select pack, it can be really helpful progressing the last missing cards but having blue and purple ones shouldn't have been too much to ask for (maybe in the extended shop).