If a blocked creature gains flying after blockers are declared, it won't cause that creature to become unblocked, even if the blocking creature doesn't have flying or reach
Flubs is ideal for decks that dump their hands fast or run lots of cheap spells
When Urza, Lord High Artificer enters the battlefield, create a 0/0 colorless Construct artifact creature token with This creature gets +1/+1 for each artifact you control. You can also tap an untapped Artifact you control to add one Blue mana, and you can pay five to shuffle your library and then exile the top card of your library, then you can cast it for free until the end of the turn
Cards like Etali, Primal Conqueror have an even bigger impact on the game for only one more mana
It's still heavily played all over a number of formats
First of all, her trigger to transform is probably the easiest to fulfill