My gut tells me that the value in bug reports is as customer feedback and goes beyond the mere technical issue. For example, a dialog can unearth how the customer is using the tool, what other tools they are using, why they are using those tools, their level of experience, etc.
If nothing else, googling the domain of their email address may provide useful insights. Anonymous bug reports waste the user's intent to engage with the company. That's not to say there's not an argument for anonymous posting...on the internet there's an argument for everything. But anonymous bug reports push the needle toward less customer engagement...and maybe that's the underlying motivation because customer engagement is often harder than writing code and clearing bug reports.
My experience is that any box that anonymous users can type text into gets filled by bots. Authorization is a pretty much a solved problem in so far as it can be easily outsourced.
YMMV.