There is no single best Pokmon product only the best one for what you want to do: open packs, start playing, display, give a gift, or collect a specific Pokmon
The original European product was sold as miniboxes, each containing 3 booster packs and 1 Limited Edition "Blue-Eyes Ultimate Dragon"
Once you have [BT19-082 Yao Qinglan] in play, attack using Digimon with [Aqua] or [Sea Animal] in any of their traits while you use [BT19-082 Yao Qinglan]'s Your Turn effect to build up your digivolution cards with various inherited effects
Sure, Pia Nalaar, Consul of Revival likes this card, and it may be the best 5-drop for that deck, assuming you ever want a 5-drop in there
X Speed is there to save Frosmoth or a Dratini that has been forced out