Since it doesn't retain the list of channels one follows next to the player, it is very annoying and strange to deal with. So I'd have to lie to give it a good rating. I want to give 1 star, but give it 2, since it can hide Twitch ads - although there are other means to achieve that. And it provides replay, or more precisely access to the live VOD. This was also possible on Twitch in the past by clicking on a link within an instant clip from a stream that's still live. I think this functionality would also be better as a separate addon, instead of using this strange, inconvenient player. What's also annoying is that the dark mode of the chat always gets reversed when one hides the chat.
P.S.: Since I can't answer to the developer's answer... Whatever he means by "instant replay", if there is anything else than "Rewatch this broadcast" where it opens a VOD link at a specified amount earlier, it's impossible to find anyway. Probably he has just another definition of a "VOD link", obviously it's still live but works just as a VOD when it's no longer live. But this is not even a criticism as such.