Gambling (also known as betting) is the wagering of money or something of value (referred to as "the stakes") on an event with an uncertain outcome, with the primary intent of winning money or material goods. Gambling thus requires three elements to be present: consideration (an amount wagered), risk (chance), and a prize. The outcome of the wager is often immediate, such as a single roll of dice, a spin of a roulette wheel, or a horse crossing the finish line, but longer time frames are also common, allowing wagers on the outcome of a future sports contest or even an entire sports season.
In regards to chess specifically, and playing it of course with no gambling, this is a fiqhi matter, where our esteemed Maraji' have different verdicts.
For example, A.U. Seyid Sistani (may Allah prolong his life) says that it is absolutely haram.
As for A.U. Seyid Khamenei (may Allah prolong his life), he says if it is commonly seen in the custom of people ('urf) as a gambling instrument, then it is haram, and if not, then it is halal.
You must refer to your Marja' taqleed for this fatwa.
And Allah knows best.
It is because there are hadith specifically prohibiting chess.
Ayatollah Khamene'i allows chess if it is not being used for gambling, but in general the traditional view is that it is not allowed.
God knows best.
If there was really no risk of loosing in "matched betting", you would have seen all wealthy companies investing in it. Matched betting is a type of calculated betting which means it is a type of gambling with small percentage of risk. It is a betting and betting is not allowed in Islam.
Yes this practice is considered as gambling. In general any practice which involves a prize achieved from the property of the participants is gambling.