Steem is based on a solid platform of value brings value through its growing network of developers, authors, photographers and artists it provides a pseudo tangible "product" for investment. So I understand why Steem is a good investment.

Why Bitcoin? Essentially Bitcoin's value is scarcity. It's a totally make beleive currency that seems to have gained traction. I think that Bitcoin is more likely to "level out" as more alt coins come on the market with faster transaction times and greater liquidity.

Why not Ether? Ethereum is build on more than a coin by offering smart contracts and distributed applications (including the one that built Steem)