I started playing it recently both in Modern and Wild and it seems that the game is full of bots.
About 1 in 3/4 battles are bots.
How do I know?
Despite that many opponents seem to have generic names (only number changes at the end of the username), they have their units set up right away.

I easily checked it by making myself lose many battles by quickly choosing only 1 weak monster and clicking "battle" as soon as possible. It took about 5 seconds to configure my side.

The battle started right away (although the mana pool was high). It means that the opponent spent no time configuring the units. It suggests that the opponent was a bot.

After that I did a quick google search: