I don't think those are your real questions, but I'll take them.
21 hours ago, ptietz said:
1. Is there any experience in doing so?
Can you have material design while still maintaining a "gamey" feel?
Are there any traps or bottlenecks to consider, that people already ran into?
What do you mean by a "gamey" feel? There are games like Chess, Go, Checkers, Mancala, board games that have been played for hundreds or even thousands of years. They're the longest running games in human history, would you say they have a "gamey" feel? There are probably millions of web games from things like Slither, Generals, Alter Ego, A Dark Room, do they have a "gamey" feel? There are other games like Hearthstone or Civilization that are highly turn based and not particularly animated, would you say they have a "gamey" feel? There are first-person shooters, real time strategy, platform games, puzzle games, one-tap games, and many more; would you say any of those do or do not have a "gamey" feel?
Certainly there are traps and bottlenecks. EVERY system has limiting features. It is far more likely that the liming features will be your own implementation, but you might bump against the limitations of their system.
21 hours ago, ptietz said:
2. Is there any analysed data (i.e. usage statistics) available?
How well or poorly is it accepted by players of games compared to users of application software?
How well does Material Design perform in games? Is it just as intuitive as it is in apps?
Google probably has their own statistics. Some larger companies have their own statistics. There are probably market research firms who have done some of those things. Unless you have a pile of cash none of those statistics are available to you.
As for how well it is accepted, that's irrelevant. Players don't particularly care what technologies a game uses. You don't hear stories that that game reviewers are critical of a game because the developers use WWise, or instead use Miles Audio, or how a game absolutely must be written with XAudio2. You don't hear a game reviewer say "I'd give this five stars, but because they use Lua for scripting, I'm bumping it down to three." Instead, people care about how the game feels to them.
I think your REAL question is if the tools will work adequately for the game you want to make. Those answers depend almost entirely on the game you want to make. Since we don't know what game you are trying to make, we don't know the visual style, or the control style, or the responsiveness style, we can't really tell you if the system will work for your game or not.