I delete almost every spam emails in my spam folder. I don't like them filled in my email account.
Basically you get emails which contains things you are not interested. Talking about me, i get many spam messages regarding medications. But i don't use even a Paracetamol So it is useless for them to send emails to me. But there may be some people get benefit with them. So they will worth 1% of the total spam emails they send.