Hey Ade,
You’ve touched on something which we are constantly questioning ourselves. To many, the queue system seems at odds with the inclusive ethos we look to embody as a company.
Ultimately, we would really like to move away from this in the future. To be completely honest, growth has been a necessary focus for us as we move towards launching as a fully fledged bank and the referrals/queue skip really helped us drive this. Without, we’d have struggled our way through multiple funding rounds and may have found it much more difficult to obtain a banking licence.
Whilst it’s far from perfect, we try and make sure that opportunities to skip the waiting list are as democratic as possible and that everyone, no matter what their social standing has a chance to enjoy this sort of perk. The in app referral system is just one way people can do so. We also run regular competitions via our social media channels, host landing pages for campaigns (such as the Old Street one recommended to you by @billinghamj ) and often manually bump users up the queue purely as a goodwill gesture.
You raise a good point about other sorts of incentives, we have tons of Monzo swag here at the office for exactly this reason (no cards with kittens yet 
️) , and think we should probably focus more on these sorts of rewards for users.
In short, every point you’ve raised above, we’ve discussed and considered as a team. The queue skip system won’t be here forever. I hope this makes some sense and goes some way to addressing your concerns 