But why would having a "valid" email address help you more getting payment?
At most you may send reminders, but even then, those may end up in a spambox?
Even once you've verified the email, you have not much of a guarantee it will stay verified/working long. That's more the subscriber's problem, if they want to continue to use your product.
It's easier to create many disposable email addresses than "real" email. To get a new "real" email address, you need to fill a lengthy form (e.g., try it on Gmail.com now) and it's not easy to automate the process. But it takes only one-click to create a new disposable email address. Some disposable email providers also provide APIs, so you can create addresses in batch.
People may exploit paid services by creating many new accounts -
1. Free trials: When trail period ends, create a new account.
2. Services with metered billing: Use the service, then refuse to pay. Then create a new account. Then refuse to pay. Then create a new account...
Of course, (theoretically) if the service provider has enough resources (i.e., money, time, knowledge...), they can always find a better solution than banning all disposable emails.
> It's easier to create many disposable email addresses than "real" email.
The difference between real and disposable is manufactured. A novice could register a domain, sign up for email hosting, and set up a catch all for cheap.
At most you may send reminders, but even then, those may end up in a spambox?
Even once you've verified the email, you have not much of a guarantee it will stay verified/working long. That's more the subscriber's problem, if they want to continue to use your product.