Dumb way I have been describing the harm of crypto:
Because when say, you use your computer to calculate 1+1, it just straight up calculates 1+1. It doesn't need to grow more complex.
Everytime say bitcoin or whatever calculates 1+1, it needs to leave a record of that 1+1 that is unique to that calculation. In doing this, it requires bitcoin to become more and more complex, even for simple computations. Every time 1+1 is done in bitcoin, it is more complex than the last time it was calculated, requiring more processing power. Everyday computing doesn't have this problem, power consumption doesn't have a need to grow more and more complex. Every time you put 1+1 in your PC, it requires the same amount of processing power.
By nature bitcoin is designed to grow more and more power hungry, individual PC's do not.
Every day I am thankful that other people are better at explaining this than I am