What about the retailer that sold the perfume? They'll usually auto sign up the customer to their product emails and/or adapt their landing page to customer's interests (like Amazon).
Under GDPR this kind of self advertising falls under legitimate use of an email address, so if you inform the user you'll send them the emails, it's legal to do so without explicit opt-in. (AFAIK IANAL)
Fortunately, at least in the EU that's illegal.