Feeless, near-instant transactions could displace a lot of the coins out there, if they can solve all attack vectors.
Bitcoin has good liquidity and been tested though many drops and spikes. Each time it makes the network more antifragile. No one wants to trust a new currency where a large percent of holders have never been tested and might sell off their entire share at any time.
Bitcoin is pretty much impossible to change now. It's just too big for that.
Example: Segwit voting was available in October 2016 but didn't manage to get significant miner support, finally got activated in August 2017 after a lot of controversy, and is still not seeing convincing adoption[1]. It seems to be stuck around 10%. If a soft fork is that difficult, then more drastic changes must be impossible.
There are real competitors to Bitcoin Core today, and Raiblocks is not one of them. Your value proposition cannot be "like Ethereum but fractionally better because volume is two orders of magnitude less". There are even interesting coins like Aragon, Po.et, SALT, Aeron, district0x that actually do things Bitcoin doesn't do.
Competing for "payments on the internet" is a losing battle, of which you can find hundreds of other pumps on coinmarketcap. They all have nice landing pages about how the blockchain is the future and this is the new way for money and banking. That's a clear sign there's no future in a coin, because the founders can't come up with anything but "let's make Bitcoin faster".
Obligatory disclaimer that I don't invest in any of these things. I'd rather have people invest in curing disease, space travel, longevity research; things that affect the physical world and push humanity forwards. "Like Visa but fuck Visa" is not a compelling pitch.