I enter most of my transactions on my phone and I agree that the mobile experience is key. Dollero is a responsive PWA so it can be used offline and can be installed by "Adding to home screen" on a mobile device resulting in an experience that is very similar to a native app. I'm continuing to polish and improve that part of the app.
YNAB is a great product and is ideal for people who are new to budgeting and desire an automatic bank account import.
Dollero is for people who want an envelope budgeting system, like YNAB, but are price sensitive and value their privacy. Dollero is free to use. Data syncing between devices will be a small monthly fee (currently free while in beta) making it much more affordable than YNAB, especially for folks in low income countries. Dollero respects your privacy, your data stays in your browser and is synced directly between your devices. For existing YNAB users I've added back some features that were removed from the new YNAB like multi-month view and carrying negative category balances.