Using a separate email address for each site is smart, but creating a separate email account for each site is going to be very tedious, and I imagine Google, Yahoo, etc are going to stop you very quickly after you've opened 20+ accounts with the same phone number.
(Use a catch-all to have different email addresses for different sites, because when one gets hacked, then the damage is limited.)
(Use a catch-all to have different email addresses for different sites, because when one gets hacked, then the damage is limited.)