The cut in the duration and value of benefits may do something to improve the supply side of Germany's labour market, encouraging people to look for jobs rather than subsisting on state pay-outs.
Also, mortgages have a duration (a calculation of the time it takes to get paid back) that is a variable, hypothetical duration that varies with prepayment speeds, so a short duration mortgage portfolio is not protection against a sudden increase in interest rates, because if interest rates rise the duration will rise which hurts the value of the bond.