Interoperability

In recent interview Charles says during banter around fees not being free on Bitcoin at the moment…but then says Bitcoin fees will be free…? Is that because of the side chain tech IOHK has developed? Is he foreshadowing that Bitcoin will use Cardano Blockchain to improve its performance? If so how does that happen? I might be over interpreting things but it seems like when Charles discusses the problems with the likes of ETH or Bitcoin he then makes a final statement…but they are here to stay…
Is that because Cardano is going to fix their problems? Are there problems only fixed if they sidechain with Cardano platform? Ir am I just very confused?