I hope this question isn't too broad, but I'm curious at to what the difference is in tone (typically) between 'lead' and 'rhythm' electric guitar (particularly from the point-of-view of rock/hard rock music). Many electric guitar amplifiers have different channels for 'rhythm'/'lead' or have a switch to toggle between two modes. Is the difference just eq-levels, or is there something more?

Also, aside from what the difference is, why is this distinction between 'lead' and 'rhythm' tones desirable?

I hope this question isn't too broad, but I'm curious as to what the difference is in tone (typically) between 'lead' and 'rhythm' electric guitar (particularly from the point-of-view of rock/hard rock music). Many electric guitar amplifiers have different channels for 'rhythm'/'lead' or have a switch to toggle between two modes. Is the difference just eq-levels, or is there something more?

Also, aside from what the difference is, why is this distinction between 'lead' and 'rhythm' tones desirable?