Congrats, Serie1926! When I paid off mine in 1998, it was great being able to cover all my monthly expenses with one biweekly paycheck. That was a big step towards my FIRE although it would take 10 years to get there. But paying off my mortgage enabled me to switch to P/T work in 2001 and I could still easily cover my greatly reduced monthly expenses.
The options which opened up after paying off my mortgage and being debt-free were crucial to my FIRE.