there is a mix up in the article of the types of wallets; in general there are 3 types — 1.an exchange wallet, 2.a wallet from commercial provider, 3.blockchain wallet;

business model applies only to #2; for details please check -

https://www.quora.com/What-do-I-need-to-know-before-creating-a-blockchain-wallet/answer/Paul-Arssov