It has changed my inner hesitation to deal with exact financial situation and where my money goes to a good understanding on how much money I have planned for which purpose and priorize where my money goes (or shouldn't).
This gives me peace of mind. For this, I am willing to spend money. I think 15$/month is worth it. (Even without Bank-Syncing).
Of course I could achieve this by other (cheaper) means, but then again I like how frictionless it makes managing my situation. And economically the return of invest in my first year of using YNAB payed for it for quite some years ;)
As someone dealing with two currencies, I can recommend RMillan's Plugins for YNAB [0].
Edit: Not affiliated with YNAB, just a simple user somewhere in switzerland
YNAB has taught me one thing (they had a whole philosophy of budgeting section when I started using it): budget for your expenses ahead of time. I pay yearly, I've been setting aside its monthly price along with my utilities for years. Another point of their philosophy which I agree with is a budgeting tool saves you money in the long run. I'm pretty sure it saves me more than $15 a month — with good budgeting practice, you can choose yearly billing on many services instead of monthly, which often is cheaper.
I've used this one for so long I really am not interested in learning something else, and in the grand scheme of things, I've spent almost twice that for a takeaway dinner yesterday. YNAB is as expensive as a pizza in London.
Lastly, I don't have big uses myself, but money tends to get complicated with time. I have a current account, a savings accounts, a business account, some crypto I bought years ago, a disposable credit card for travelling, my Vanguard investments. It's good to have them all together in one place. It's good to have a nice chart showing me my net worth change over a decade.
I knew I wasn't achieving the goals I had with my DIY spreadsheet and mint.com, and once I started using YNAB everything came together very nicely.
That is exactly what I hope to express in my sibling comment. Increasing the friction (be it UX or multi-device usage) might make my hesitation to manage my financial situation bigger and I might cease to manage it. This would be quite a bad scenario (well, at least for my savings ;) )