"Personally I never lose any sleep over the possibility of anyone hacking into my not-very-interesting emails"
You might not want to lose sleep over it, but criminals are far more likely to hack into your emails than the government. And the worry about this is not, actually, that someone in the local police will knock on your door about those adult websites you were visiting (which lets face it is the actual, unspoken concern usually :-) ) but that people with evil intent will steal your password, your bank account details,even your online identity. Not sure I really understand
"Now with the real-time access, scammers could be able to accurately reference recent online activities, making their fraudulent emails appear all that more legitimate."
What matters is content, not really "metadata". We always need to be alert to the scammers etc, but the real worry for many rather is that crypto-cracking "back doors" might be introduced into comms for crime prevention purposes, when want we really need is more encryption not less. When we read that Islamic terrorists used whatsapp to communincate before one of the London attacks, it gets any self respecting Home Secretary jumping around. It's hard to know who how you can ever really keep ahead of technology. You or I can, if we really want to draw attention to ourselves, easily encrypt our emails using encryption that the top crypto-devices in the world would take years to break. At least with the metadata at its disposal if necessary there is something for legitimate "snoopers" to go on.