The Platinum Membership allows you 12 instances of the scrolling ticker and 12 messages per instance. If you only need one ticker at the bottom of your live stream, and 12 total scrolling messages is enough, then you only need the Gold Membership. You would want the Platinum if you had a reason to need a fully different group of scrolling tickers. For example, in a Live Stream show if the bottom scroller says something like, "Welcome to my Live Stream Show, you can follow me on twitter @mytwitterhandle." Then the second message on that same page said, "Follow me on Facebook @myfacebookhandle." And then a few minutes later you had a guest on your show and you wanted that scrolling ticker at the bottom to load only ONE message for a while on your show which said, "Follow our guest on twitter @guest_twitter_handle." Then you would want to be able to load "multiple instances" of your tickers.
The Gold membership however would allow you to load all three of the above scrolling tickers onto ONE instance of course, but then on each new scene they would load from the beginning and scroll through all of them. Versus being able to default the new instance to exclude the messages which were not about the guest.
Here is a simpler explanation:
Picture instance number 1 of your scroller loaded on scene 1 of your show.
Instance #1: Contains Message-1, Message-2, Message-3, Message-4
All these scroll for five minutes of your show.
Then you change scenes to scene two and load Instance #2:
Which contains Message-5 (not included above) and Message-6 (not included above)
So Instance 2 loads completely different content from Instance 1.