When you first start playing the game there is a special coin room for "Hack" tier players only that is only 25 or 50 coins to play. Once you advance to the "Amateur" tier this room disappears.
It is there for beginner players to learn the game without having to wager too many coins or being forced to play against more skilled and/or better equipped players.
As far as forcing you to play these matches when you start out, it wasn't like this when I first started playing a few years ago but maybe WGT changed it so that you must play this way until you have played X number of H2H matches or advance to Amateur tier as some kind of safeguard for beginning players from losing all their coins in the first 5 mins of playing.
Maybe a WGT admin can clarify?