there are many crap coins, with no real block mining competiton. this most reward can go to a botnet/malware, whilst also being such an unknown crapcoin no one spots the abuse happening to care to even want to fight it..
there are some that make blocks in seconds (meaning far less than 10cent of CPU power to make a block) but had coins market rate at more then 3x of that cost.
it doesnt need to be coins worth $150 a coin at 430coin a day rate(like monero) to make it worth cheating people
scammers, hackers and just generally malicious people can do it on many coins.
30,000 botnets using a crap coin of 100 coins every 60 seconds where cpu cost is
0.04kwh electric
=0.02 per cpu/hour
=0.000333 per cpu/min
=0.00000333 per cpu/coin
=0.0999 per 30k botnet electric abuse per coin(not actual cost to hacker. but network underlying value cost per coin)
~$0.10 network value per coin, but coin market rate is $0.50 per coin meaning $50 a block(minute) meaning $72k a day, where botnet gets most of the coins per day thus most of that $72k without causing speculation fear/changes of prices
compared to monero $64.5k a day where botnet would get less share of that amount and would cause more speculation fear and drop price thus lose out more.
so yea there are many many crap coins that are not even worth a dollar each. but adding up how many coins are produced and the lack of competition meaning a botnet can get a large share of the daily coins means they can botnet/malware mine a few different crapcoins and net a nice hefty reward