Well fun frm the meaning:
fun
fən/Submit
noun
1.
enjoyment, amusement, or lighthearted pleasure.
"the children were having fun in the play area"
synonyms: enjoyment, entertainment, amusement, pleasure; More
adjectiveinformal
1.
amusing, entertaining, or enjoyable.
"it was a fun evening"
synonyms: enjoyable, entertaining, amusing, diverting, pleasurable, pleasing, agreeable, interesting
"a fun evening"
verbNORTH AMERICANinformal
1.
joke or tease.
"no need to get sore—I was only funning"
When you are playing a gambling game, and you are winning. one of your feeling is like those in that definition. Others play gambling game for amusement. Amusement that while having fun they can also earn money. If you are winning of course you will enjoy the game thus saying that the game is enjoyable.
Yeah,
And addition to what you said,
Gambling is made to entertain people so as to entertain means to give fun, to those who play it,
Basically the gamblers.
Gambling is fun when you win sometimes, yeah.
But the true fun in gambling is the feelings that you felt from it like thrill and excitement,
And that is how the game should give to as.
That is why it should be considered to give fun.