Any fee break from GBTC is a positive, but it isn't enough (most likely) to get people to switch given that capital gains taxes would be due on the sale. New money would go there and one hopes that the competition would encourage GBTC to match the price. Competition is good for everyone.
If I recall it correctly it's a mere 0.15% less! One would argue that on big numbers even a tiny 0.15% variation can make a difference but still it is quite high.
GBTC is not like an exchange where I go in and out with ease and I don't see this as an incentive to leave the GBTC boat to go on another fund. We'll see how this plays out.