No, they will not do the same job, the Eheim fine pad is very fine, at least an order of magnitude smaller particle capture than floss, and that only with very careful packing of the floss. I suspect in most circumstances the fine pads are effectively closer to two orders of magnitude finer than floss.
I personally would never put an expensive filter with a 10-20 year operating life at risk to save a few cents running cost. That to me is like adding regular gas to a car built for high test - it may work after a fashion and for some period of time, then it costs a lot more money to repair than was saved earlier.