SD-WAN packet fixing & Optimisation,.. does it really work

Hi All, So I've been going back and forth with some people in my team over SD-WAN & Optimisation tech and wearing my Admin type hat,.. well tbh, I don't believe that it actually works as described. Far too many times I've been told about product bla that will do this amazing thing and make my life amazing & simple only for management of my workplace to fall for it, we put it in and then it does a mediocre job at best. Essentially we have one guy in our team who is pushing Silver-Peak massively (to the point where I think he must be getting a kick back) saying that it will make our Office 365 run so much better bla bla bla, however this guy has questionable knowledge on how the inner working of tech works and generally just know what current buzz works to say.

So mini rant over, does this stuff actually work? If i put in a silver peak router & server in azure will it somehow magically use less bandwidth when downloading files from SharePoint? Will it somehow make all of my emails smaller and allow us to de-dupe email traffic,.. even though said traffic is encrypted? Also the whole SD-WAN premise looks to be geared towards businesses with multiple offices that want links in-between them, however everything of ours is in the cloud so I don't really see any benefit with that. The only thing I can see is that it can repair dropped packets through parity information in the packets that did arrive. however thats not an issue that we really have.

So I guess what I'm asking is, does anyone use this stuff that can honestly tell me if it works as described who doesn't work for the company selling said product. Every review I've read that says it works all looks to be written by someone who works for the company of the product they are reviewing.

thanks in advance for anyone that has the time to comment.