For the longest time we asked customers for there e-mail. The assumption was that by having a form of contact we could improve metrics. Asking people to return, sending out personalized recommendations, or security reasons.
But not in every case is asking for e-mails or even creating accounts necessary. We often times underestimate how much friction this creates. Even the basic account registration is something more and more people are hesitant to do.
With years of experience getting there accounts hacked or spammy mails. Customers are not so open anymore to share there contact information.
Often we need them anyway, having no point of contact on e-commerce stores are hard. Same goes for paid applications or subscriptions.
But as we ask software developers to not build what isn't needed. We also shouldn't ask for customer data first and figure out a way to monetize and use them later.
It might be surprising by how much you can improve metrics by removing the need for e-mails. Something that is worth considering based on the environment you are in.
As not everyone is in the position to revert this in there product. It might be still worth it to explore some fundamental options. We talk a lot about the Social Media Log-In systems with oAuth. But there are also new ways with Apple or E-Mail based (link for log-in).
Sometimes we accept certaint elements as given, but we shouldn't. Experimentation and looking at your key metrics helps to align the product. There is much less given and set in stone!