What purpose do low interest rates serve?

Cui bono ? Whose good ? Low interest rates are good news for mortgage holders on variable rates. They are bad news for savers. They have not translated into any considerable increase in bank loans to firms with cash flow problems (the banks are understandably sniffy about taking risks) and relatively few firms are looking to borrow to invest. When bank loans are given, the interest rates are many, many times higher than bank rate - as are the rates charged by credit card companies. To the extent that the economy is recovering, this seems to be due to restocking and to cheaper exports in the wake of the low value of the GB �. Enlightenment please !