You're jumping to conclusions without reading it in detail. Everything is clearly spelled out. Lets break it down:
This letter constitutes an official document issued by the Department of Immigration, Refugees and Citizenship Canada. You can provide a copy of this letter to prove that you are a permanent resident of Canada and to apply for government benefits and services for which you are eligible, until you receive your permanent resident card.
To me, this means that you can use this letter to apply for a SIN number, medical card etc.
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This letter does not replace the permanent resident card; you are still required to submit the documentation to obtain your permanent resident card. If you have a Confirmation of Permanent Residence (CoPR) document in-hand, please send it along with one photo that meets our photo specifications to the address listed above.
IMO you should not send this letter to get the PR card. Why would it even state "if you have a [CoPR] document in-hand" as a condition if this letter was enough? You need a real CoPR document for this. Whether they would actually accept this letter in place of a CoPR I have no idea. This is a new process and I doubt anyone has given it a try yet.