Gambling can be played in a variety of ways. You see, would it class as work if you are not paid in money? Does it class as a purchase if you decide to pay exchanging something? My take is that it is as long as you put there something that has value, from your own time, reputation and even intangibles... or works of art or anything. Time is money as they say.
Exactly because even though a player does not deposit case directly to the casino to play with, he/she still invests one thing or the other ranging from their time efforts and even devices that are used it all involves values as you have rightly said.
But in most cases, society does not consider those as gambling, since the belief one can only gamble by staking some money and every or aspect is just regarded as just playing for fun.