buncha indie games dropping reveal/release trailers because of summer games fest. the only thing i'm feeling much interest in is finding out why these devs are allergic to putting gameplay in their advertisements

i'm making firedog, a sunshine-like with dogs in it
buncha indie games dropping reveal/release trailers because of summer games fest. the only thing i'm feeling much interest in is finding out why these devs are allergic to putting gameplay in their advertisements
Because it's a lot easier and faster to develop an interesting animated story trailer (basically just visual and audible art) than it is to develop gameplay (both of those, plus game design and programming)?
Like, I'd love to show some sort of trailer for the game I'm working on. Unfortunately, I'm mainly a programmer so while I have some game design and a mostly functional engine put together, that's not enough for a trailer. It's a lot faster if you can do visual art first, because people will be a lot more receptive to visual art than to code.
there's nothing wrong with some promo art or animations, but if your trailer contains almost no actual gameplay, who are you selling it to? how will prospective customers understand your experience? so many indie games that i've just straight up forgotten to follow up on over the years because the only thing i remember them as is "that really cool rabbit with a gun trailer"
not even a matter of creating new gameplay to show off, just if you're advertising a game, show anything!