Why use Xverify, or any email verification service?
Cold email marketing is hard. You have to worry about open rates, response rates, and if your campaign is hurting your email deliverability. Your failed marketing campaign could actually make your internal company emails and emails to current customers not get delivered, because you sent out too many emails that bounced back.
Whether you've bought leads, scraped them, or just had people give up email addresses in exchange for an e-book on a blog post, you need to make sure those emails are valid before you do anything with them, to protect yourself.
Xverify checks the validity of your email lists to make sure you're safe to send emails to those addresses.