No it is not advertisement only, but the main system is that amp will be required everywhere in synereo, whether you want to share something, or want to advertise, or want to reshare, or if you are a content creator then when you show your good content then you earn, but the main point is that there will be no censorship or getting revenue from advertising by company. All is for the public, this will be first fully decentralised social network.
And for those who compare it with steem, then this is not some ponzi or other simple or earning system. This is a social network, a reddit like news site like "front page of web" or web 2.0, a system to compensate meagre earnings of content creators of youtube and others. So now you know
whaaat this is!

No content creator would care for Qrator if AMP is worth nothing. No curator is interesting in curating if AMP is worth nothing. The value of AMP doesn't come from rewarding people. There have to be people outside AMP that want to get in because getting in AMP is beneficial for them. Curating posts is only beneficial for selling AMP. So there has to be some kind of advertisement model or else AMP will collapse. Or maybe there is another model behind it that attracts people to get into AMP. Why does anyone need to buy AMP ? Question still not answered.