Market cap says something but not all. When you or anybody choose to invest in a project, it is necessary that you do a deep research into the project by: joining their community, having yourself trying their products.
After that, do valuations: will this community grow stronger or be less and less supportive? Will these products be any relevant for the future anymore?
Low and high risk is about how you do a research and invest in a coin with little of knowledge or a lot of knowledge..