The reason partly for their being so many bitcoin wallets on the market is because many bitcoin exchanges have native wallets as part of their service. We realized early on that exchanges although their primary service was to offer the buying and selling of bitcoin, a byproduct of that was letting users store bitcoins natively on their platform; hence, many exchanges are also bitcoin wallets.
Read more: http://bitcoinx.io/news/articles/any-pr ... in-wallet/