Bitcoin Versus Ethereum: Room For Both?

Ethereum has increasingly become a problem for the Internet's millions of Bitcoin faithful. It goes against Bitcoin maximalist dogma, for one thing: if the 21 million eventual total Bitcoins in the world are the only genuine, useful, well-supported cryptocurrency... and if everything else is imitative, manipulated, or "centralized" junk... then what is this thing Ether, and why are all the Ethers in the Ethereum collectively valued at US $894,488,591 today, even hours after Bitcoin's block halvi...