I disabled voicemail on my cell phone. My Dad did it, because all he ever got was spam. Likewise, 95% of the voicemails I had were spam or doctor appointment reminders. In either case, I really don’t want to sit through a voicemail. So I disabled it, and it’s been great.
If you want to do the same, just call your carrier (or if they are very neo, go on their website). It’s a product that people want apparently, so you might even save money doing this. I think it keeps it simple, because the first thing anyone does when another person’s voicemail is full is email. So it just skips a step on their behalf.
Voicemail wouldn’t be so bad if cell carriers did what office phone providers do and transcribed the message into a readable email. But they don’t, so it probably just makes more sense to turn it off.