I understand you're new here and are looking for some answers but I do not appreciate the perceived (and can be totally wrong due to the nature of text messages, not verbal where emotion can be honed in) negative attitude on how this works since it doesn't serve you.
There are plenty of other payment options for you to choose for with Trusted Dealers, payments that are safe to use and are not necessarily PayPal.
Just like any other business, the sellers/dealers decide how to conduct their business and they don't have to provide anyone with shortcuts. Thankfully, those who are members of RWI and decide to support or patron RWI get extra benefits and our Trusted Dealers have willingly matched those benefits.
When it comes to the Member to Member (m2m), the same stands. Sellers choose the buyers and they set the rules for their sale. I personally do not sell to certain part of the members and I state that very clearly on my sales and most do as well.
These restrictions you are finding are due to countless bad experiences caused by amateurs or actual scammers that bring such hassle to sellers and TD's alike.
the whole watch buying process seems purely based on trust with no paypal offered or any guaratee of delivery of said item ,
And this does not make sense, if you pay for an item, is that not guarantee of delivery?
Of course it has to be on trust, this is an illegal industry where all laws and rules are against it.