What value does your system provide by limiting addresses to 100 characters and the given regex. Why not just allow any input and validate the address by attem

What value does your system provide by limiting addresses to 100 characters and the given regex. Why not just allow any input and validate the address by attempting to send to it. It's really the only way to tell if its a real address. What abuse can a person bring on your system by having a 200 char email address? That should be nothing in terms of server load.