Here's a summery of what all the fuss is about:
Bitcoin could really take off today, but many people say that it will be a big "mehh" and Bitcoin will continue to march along as usual.
WHY IS THIS ETF SUCH A BIG DEAL?
It's all about liquidity. While there are plenty of places to buy bitcoin, many investment funds can only hold assets that meet certain regulatory standards—such as approval from the SEC. If the agency approves the ETF application, money managers who want to include bitcoin in their portfolio are likely to jump in. Meanwhile, millions of ordinary people will have an easy new way to buy the digital currency. I can't really phrase it any better than this quote from BitMex, a bitcoin analysis site:
If the SEC approves the Bats rule change, all manner of American muppet retail investors can yolo into Bitcoin via a regulated ETF. The pool of eligible money that can easily obtain exposure to Bitcoin will dramatically rise. There are various predictions about the amount of money that could flow into Bitcoin. In short, it will be Yuge.