From how I understood it.
An SMT (ICO) is funded with STEEM only. You can use other cryptos buy you must convert to STEEM first. This will drive demand for STEEM.
You need Steempower to run an SMT because SMT's require bandwidth to use and Steempower provides that bandwidth. So the more successful your SMT the more bandwidth/steempower you need. This will drive demand for STEEM.
More info here:
https://steemit.com/steem/@ned/explainer-value-flows-on-steem-with-smts-video
Thanks! Great explanation and info, makes sense.