These insect and animal fights become popular in some provinces because there are no means for these people to play gambling and they want to explore something new, so they create spider fighting, insect fighting and so many other forms of gambling that involves animals and insects.
True, especially in some part of Asia in the province its very popular, because no other gambling activities in their place or go to the closer place that they go gamble, except that insect fights. Betting on insect fights is easy to know and you can win instantly, that will not too long.
Bet with insects i think it's very old-fashioned, now all the popular bets are on the table. Especially if you are familiar with the internet, everyone can bet on the bed by just using their smartphone.
It may also be that in the future these ancient bets will disappear and be replaced with more modern ones. Even in this forum there are various types of bets and gambling games that are easier than having to go to the insect bets.
In my country there are animal bets such as insects, so this bet is very popular in the states of Asia. But now I rarely see bets like this. All have been replaced with cards, dice, and everything is easier.