Faceless male protagonists are fairly standard in a lot of adult material. It's not the norm, but it's not unusual. Several games on this site do a weird, ghostly male figure for the sex scenes in particular. I'm thinking of Harem Collector for that, but I'm sure there are plenty of others. It's purposeful for those who "self-insert" while going through the material, and want to picture themselves. Arguably, it might just be because artists don't necessarily find the male characters interesting, or are just lazy that way.
That said, it is a bit affected in this case. We get shots of the MC's scraggly chin whiskers, for instance, which always mystifies me. Not just why we get those shots, but why anyone would think that's a good look.... The only other time I've had a problem with it is in earlier chapters when they give us the MC's disembodied tongue waggling in the air to note some oral sex act. The fuck is that, man?
