Melira is a one time thing and it can't happen again
For example, if the exiled card is a land card, you may play it only during your main phase while the stack is empty and only if you have an available land play remaining.
Urza, Lord High Artificer isnt a commander that's here to play fair: It's one of the top cEDH commanders (which is even more impressive given the hard time mono-colored commanders have at the highest tier), and it already has another crazily priced printing: Its Mystery Booster 2 version hovers around $380
Functionally, the card is the same as the regular version at number 10 - Lands that can tap for two mana are great
These days, I use Maya for 3DCG illustrations and Photoshop for both finishing and creating effects for 3DCG illustrations or for drawing 2D ones
One of the better and weirder payoffs for this mechanic is to help with deck-building restrictions