Virgin Atlantic Points to hopefully uprgade..a question

Me & my partner are flying to South Africa in October for our honeymoon, a friend told me to check up on Airline points schemes, credit card points etc, which over the past week or so i've fell down the rabbit hole of this world i'd before never really paid attention too.

So far i've got myself an AMEX gold which im collecting points on, and i've signed up for all the big airline reward schemes etc.

I recently came across an interesting article however, you can apparently buy Virgin Atlantic Points and they are currently running a very generous offer where if you buy 100,000-150,000 points you get a 70% bonus, the article stated that buying around 100,000 points would equal around £1500.

Now, my flight i've found when checking the box for 'points only' states Premium would be 50,000 points and an extra £700 for both of us. If my logic is correct, surely buying the points and using them for this flight makes the most sense? I'm unsure though as i said this is my first dive into this world so im unsure if what im proposing is correct.

Secondly, I tried to access the page where they sold points and it told me: Before you can Buy Miles, you must have made at least one Flying Club Earning or Spending transaction.

Does this mean i have to catch a flight somewhere with Virgin and earn some points on that flight before i'm allowed to buy points?

Thanks for any help or insights given!