I can't say it's the only thing I used to track my progress to FI, but I do use YNAB to keep track of my net worth, including my FIRE funds. I have my retirement accounts from work (403b, in my case) and my Roth as Off Budget accounts so I can track balances. I update each account on the first of the month by just adding or subtracting the difference from the previous month's balance. So, I don't track contributions vs. dividends vs. gains/losses. But it allows me to see quickly how much money is in which account and what my overall total is. For my house, I used two Off Budget accounts: one for the value of the house (updated every 3 or so years as my housing market is pretty stable) and one for the mortgage balance. I would update on the first of the month with the amount that went to principal from my on-budget PITI payment. When I paid off the mortgage, I just closed that account and left the account that showed the value. When I use the Net Worth reports, I can include or exclude the house value as desired by selecting the accounts to consider for Net Worth.
I should add: I still use YNAB4.
I also tracked these things in a spreadsheet so I could play with changing contributions, forecasting, etc.