I agree. The presence of photographs is not a must factor. it also does not mean that the team is a scam or that the project is a scam ... just people are usually calmer when they have access to all the data regarding the project in which they are going to invest their money.
And I say that times have changed a lot. Today, investors have become wiser and try to study projects as carefully as possible. Everyone is afraid to get on the scam. Therefore, the lack of photos or some complete information about the development team can scare potential investors. Although I personally invested in a project where the team remained anonymous.
It is clear that the lack of photos of the team on the site is not proof that the project is scam. People can for some reason hide their data. It is their right. But better when more information about the team.