I put it all down to options for the resepective vendors,...

I put it all down to options for the resepective vendors, however CallCabinet isnt partnered with the telcos is the biggest difference.
If they are, Im surprised its not listed here: https://www.callcabinet.com/technology-partners/

Being avaliable on Cisco, MS Teams, Zoom pretty pointless as its all down to all the partners out there pushing which ever product is incentivising the best commissioning to them, atleast in my opinion.
Everyone man and his dog is integrated into the above, unless you can get a foundational deal like Webex your out there trying to make sales.

Im not sure how much value the email analytics would be, your now fighting on multiple fronts with Miicrosoft, dedicated contact centre products and god knows what else is there.