If your application/website asks me to enable desktop notifications without my specific request for such a feature, or without explaining that this will become another spam source, I will blacklist it and never come back. On my phone, if an app causes spammy notifications, I uninstall it. Apps and websites can't spam without my permission, and I'm not about to start letting them.

This might be nice for you as a marketer, but as a user, I want nothing to do with it.