Don’t know when the App download was added to play store , but it does say quite clearly in the second line “to activate your card …”
Presumably the initial Android sign up for Monzo a couple of months back didn’t , however most people must have been following Monzo to take up the invitation of signing up and read something about the app - or are they just serial sign uppers ? and there were several "discussions " about the iPhone 100 quid sign up in July.
£100 is a considerable amount , but it is yours to spend straight away once you receive your card, or as mentioned previously when you change your PIN withdraw any amount you want , stick it in your wallet and top up when you’ve spent the initial amount you leave on the card
I think Ive read somewhere that the card costs about £40 to produce / register and send out , if people are not going to “test” it by using it , it does rather defeat the objective of trying to produce an Android app that works if you get no feedback from usage.