What's the point of paying down mortgage?

isadreamalie

sidneyvic said:

In simple terms...
Total repayment of £300 of which £100.0 is interest and £200.0 is capital.
If you overpay by an additional £100 you are in effect paying an 50% extra off your mortgage per month.
But there is also a compounding effect as in the second month you have a £100.00 less capital outstanding on which to have to pay interest thus not only paying a further £100.00 off but also saving the interest and it has a nice snowball effect, the more interest you save, the more of you payment comes straight off the capital.
It is surprising how even a seemly small overpayment can make a big difference. 

Clearly put