Email forwards can be really usefull if you still receive email on your old domain, but don't want to lose it or give your customers a bad expierence by receiving a bounce.
By setting up an email forward on your domain, you can ensure all emails are still received correctly.
You can change the destination of the emails anytime. redirect.pizza will give you an easy-to-setup MX & TXT record to change at your domain, which in turn will ensure that all emails are forwarded correctly.