You are right, the work should be done in stages, first release of the finished product after that participation in events to support it.
This is a matter of time and money. The most profitable at the moment to invest these resources in the work on the project. Advertising and promotion will be relevant at a later stage.
The main point is that in the later stages the team will receive a large financial resource with the help of ICO. Having it will be much easier to implement and develop and promote the project.