To be honest, in my understanding this is to prevent you from clicking on a malicious link and not letting you access the malicious page.
But this will not prevent or identify an email as SPAM, that is, it does not work as an anti-SPAM for email.
It may even help, but if you want to have email protection you have to invest in a good anti-SPAM tool.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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