We dont recommend spending your duplicates, specifically your rarest cards, just to buy a new style of playmat, card sleeve, backdrop, or coin, as you can get them by other means like events
I see no reason to play Bria over Narset outside of personal taste, which takes it down several notches
This one has the upside of not costing us a card from hand, which is nice
If you can't get the Secret Lair directly from Wizards, you might find the products on the secondary market, and a sealed one should retain all marketing components, including a potential card with your code for digital versions
The galore of Pokmon cards can be seen as overwhelming