Why does Kik need a decentralized cryptocurrency to handle payments for digital goods? They can do it with virtual credits on their own servers a million times more efficiently.
Another major problem is that we frequently see perfectly good ideas whose technical architectures are wrecked by the need to add an inefficient and unscalable consensus system to support a new cryptocurrency. For example, the original Ripple concept is a really good one, proven by the success of the analog equivalent, Hawala. Ripple could have continued on that basis - found investors for the standard open-source business model - and made a potentially useful system that at minimum would have represented good accounting software for banks (international banking is not unlike a very large scale, regulated, Hawala).
Instead they decided to raise money via a token, XRP, and because of that token they needed to add a global consensus blockchain. The result was a system that had all the scalability problems of Bitcoin, and since they didn't use proof-of-work, an ill-defined consensus model that's secured in practice by a handful of private keys, all Ripple-controlled servers(2). If we're going to go down that route, why not just do it properly and have an actual legal contract with the people in charge? And with that legal contract, why do we need XRP? Why not just pay for the service with an existing currency?
Frankly, I think most of these ICO's are transparent attempts to raise money while avoiding securities regulations. I'm sufficiently libertarian to have a mostly "buyer beware" attitude to that, but I sure as heck wouldn't want to be closely involved with one - very high risk the SEC will put a lot of people in jail over this, and the ethics of many of these schemes are very dubious.
1) https://petertodd.org/2014/setting-the-record-proof-of-publi... (read that URL link as 'Myth: Proof-of-publication needs “scamcoins” like Mastercoin and Counterparty'
2) https://github.com/petertodd/ripple-consensus-analysis-paper... Written by me under contract for R3CEV (they were considering buying Ripple apparently, and I was doing due diligence for them and their members).
They gotta start from somewhere, and the only business model that's familiar enough is the model you mentioned, and that's why they start out this way. It can succeed or it can fail, but if it succeeds they will probably branch out to other ways of making money outside of ads.