Why would a guy who not share a face photo of himself?

For context: We’ve been talking since February and got introduced by a dating app. We haven’t met yet but plan to soon as we are able to. Meanwhile I have asked for a photo of him and he told me that he thought that he did and that he would send one but he didn’t. So I was getting suspicious and did some research and it turns out he is who he says he is. The only thing was he told me he’s 25 and I’m 18, but in search of looking for his other socials and photos I found out he’s actually 37 which he doesn’t know that I am aware of this. He does not so often post on his Snapchat but when he does, it’s half of his face or just hands. It’s getting more and more suspicious.
Why would a guy who not share a face photo of himself?
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