For a definite answer, We'll just have to wait and see the release of the Appics App. But based on what I know, Appics and Steepshot are orthogonal to each other.

Appics says they operate based on the XAP SMT, which means the token you earn from using Appics are not Steem proper, there will be an exchange mechanism in place (either on the blockchain itself or via p2p market) so that people can exchange STEEM and XAP, most likely.

Steepshot works directly on the Steem Blockchaim, so just like Steemit and Musing here, if someone upvotes my steepshot post, im earning steem.

Will Appics replace Steepshot? As I said, I know for a fact that Appics will not replace Steepshot. Perhaps Appics will be one of the leading Steem SMT Apps, but since people can use Appics and Steepshot simultenously, there wont be any replacement going.

That is, of course, if/when the Appics app gets released.

I don't believe so. Appics is a much more closed ecosystem compared to Steepshot, so there's a place for both of them to exist at the same time.