I have a 30-40 year old weeping willow close to my natural pond who’s roots have turned into humongous mats inside the pond along the bank. I can pull the mats up in huge clumps and pull them out, but I have no idea if the mats are good for the wildlife habitat frogs, snakes, baby fish etc or it is a detriment. It is also a collector of algae that sits on top. I do not want to kill the willow. Any advice would be greatly appreciated.

I think it would depend on the size of the mats relative to the size of the pond. It will provide protection for small fish and the insects that they eat. While it will provide some oxygenation it will also keep sunlight from penetration.

The willow will also suck huge amounts of water.

Be sure it is away from pipes where it can get inside and clog them. I have 2 very large weeping willows on opposite sides of a stream forming at the outflow of my pond pipe. I need to keep the roots from interfering with the "flipping" of the rat guard, and also had to remove some roots with a backhoe that had formed a dam across the stream restricting water flow. The trees can be pretty, but they also suck up a lot of water and tend to break up in storms. For me, having a few is worth it.