Thanks for the detailed feedback – it’s always useful to hear, and I’ll pass it on :)
One small feature you may not be aware of: on our website, Splitwise does allow you to add group members without email addresses, which hopefully helps for the “large party” scenario. My apologies that the same feature isn’t available on our mobile apps!
We’d love to make Splitwise better for tracking personal expenses (though we’re mostly focused on splitting for the time being). For now, your best bet is probably to make a new group for personal expenses, with yourself as the only member.
So sorry for the trouble! This is on our list of possible improvements for the future – I can’t say exactly when it’ll be added, but we know it’d be a useful improvement. In the meantime, our apologies for the inconvenience!M B commented
Would save a lot of time. Definately a go, and an easy feature