From what I understood via local company legal, "necessary" means "this type of service cannot possibly exist without this data". Ie, your email may be required

From what I understood via local company legal, "necessary" means "this type of service cannot possibly exist without this data". Ie, your email may be required to use a service that notifies you via email for shopping deals. Email addresses are private data and in this case, you can't use the service without it. Making a profit is not necessary to operate a service in the same way. It's necessary for the company to be profitable but that is irrelevant to the GDPR.