Not just cheaper, but the vast majority of Indie games need the platform for exposure, despite it being so crowded. Those first few hours on the front page are when most sales are happening, especially given how abysmal to nonexistent the marketing of most small games is.
Developers seem to be under the impression that a few social media posts shortly before or after release are enough, whereas in reality, they need to create a community that is eagerly waiting for the game beforehand, spend at least as much time on marketing and community management as on the game itself.
Then again, the majority of games - and this is something few people are willing to admit, least of all their developers - have absolutely no commercial value, no chance of ever making any money, no business being on any store front and even, in the majority of cases, no business even being distributed for free other than among close friends and family. Over 12000 games were released on Steam last year. Does anyone believe that more than a few hundred of those are even worth looking at, let alone being purchased and played?
Nobody is waiting for the billionth card game or sidescroller with unattractive amateur art. Nobody is waiting for an ugly looking game with a poorly written store page that costs 15 bucks and is coming from a new, unknown developer while similar, better games are routinely on sale for a fraction as much. I've received outraged reactions from both developers and gamers for comparing some first marketed at release titles with other games out there. Almost every time, they were trying to sell their games through sob stories like "I worked seven years on this solo, surviving only on ramen and tears", as if anyone actually cares. Those stories are bonus trivia that you look up and are impressed by after having played a game and caring enough about it to read its Wikipedia article. I'm not buying your terrible time management skills and unrealistic expectations, I'm spending my limited disposable income on entertainment and escapism - and if your seven year amateur project can't keep up with a two year project by an experienced team of fifteen people even at the very first glance at the first screenshot of the typo-ridden store page, then you're out of luck - and I like weird "auteur" Indie games. Those 12,068 titles are not just competing with the other 12,067 released that year, but the entire catalogue on Steam (roughly 73,000 at the beginning of this year), as well as older games, games on other platforms and other types of media.
One has to assume that most people brave enough to dive head-first into Indie games development are either ignorant of these facts or hopelessly optimistic. We kind of need this optimism, without it we would have never gotten gems like Stardew Valley (which did not make any of the mistakes listed above though) or the equally amazing and divisive interactive art that studios like Tale of Tales have produced, but it's still frustrating to witness it pan out very predictably every time. Every single Indie success I've observed from the start was clearly on a winning path and every failure was obviously going to be a failure. I'm shocked how predictable it is, which is what gives me hope. At least success in this sphere is based on clear rules.