Psychologically, there is a big benefit in knowing that you own your house free and clear. Is a benefit
to pay cash for your house if the amount of cash you spend does not consist of a significant portion of your liquid assets and the interest rate or a mortgage is higher that what you can earn in your other investments. And finally, if the amount of savings you get from all cash deal versus a loan deal is significant. Otherwise, having a mortgage let you free up your cash for other investments.
Best of Luck,