Ignoring the price tag, there's no difference between Let's Encrypt and "other old CAs". They both perform the same kind of validation for DV certificates. Some

Ignoring the price tag, there's no difference between Let's Encrypt and "other old CAs". They both perform the same kind of validation for DV certificates. Some might even say Let's Encrypt does more than others, given that they support CAA. Other types of certificates (such as EV, which attempt to verify the business entity requesting the certificate exists and is indeed requesting it) already get different treatment in most browsers (namely the organization's name being shown in a green box).