Moneywise it depends on what you charge, what Apple or Google takes for sales of your app and its novelty in the market.
If you charge too much people won't buy it. If you offer it for free with in-app purchases people might try it depending on the excitement you can build for your game. For each sale of your game, Apple and Google extract a percentage of the price so you get less for each game sold.
Your customers might find a bug in your game and that can result in less rating stars which means less people will buy your game. Each time the OS is updated features of your game might not work and so you'll have to fix these issues quickly otherwise you will get less stars in your reviews and existing customers might revise their review reducing the star rating.
Novelty means your game must do something other games don't. As an example, you make a TicTacToe game and no one is interested in it because it looks like all the other TicTacToe apps. However, if you provide a means to alter the game rules in interesting and novel ways or alter the game play where now it requires the player to answer a challenging question or play a mini-game inside your game to win the square then maybe people will want to pay for your app.
Look at Flappy Bird, it had some appeal and so many people downloaded it. Its popularity got it noticed by other game programmers who imitated it. It also got noticed by Nitendo/Super Mario Bros I think, who said some copyrighted images were used in the game and so it got pulled.
http://en.wikipedia.org/wiki/Flappy_Bird
Don't go into game writing with the idea that you will make millions because most people make pennies on their work. The public can be very brutal to game developers and so you must know how to handle complaints and to sell your game.
Also be mindful of copying ideas from other games and you may get a notice demanding you take down your game for infringing on some other game or patent or artwork... meaing you must remove the offending item and update your customer base with a new slightly different game and they may not be happy with it.