It enables all creatures to attack right away, including your opponents
DURESS Steven Belledins art for Duress is one of the first artworks I remember seeing when I started playing Magic that had me pause to consider it
I mentioned I play it over Brainstorm often and this is because it is self contained, I don't need to hold it to milk the potential from it, as soon as I have a spare mana at the end of your turn I can fire it off and it will be about as good as it gets
Youre going to want to have a healthy amount of cards that can sneak past your opponents defenses so you can rev your speed up a bit, so some evasion like flying is perfect for a Mendicant deck
You usually have to wait patiently after purchasing, as there'll be months between clicking 'pre-order' and actually receiving your cards
But one of my best friends (who hasnt collected cards since the days of base set) still has a shadowless Venusaur that I got him for his birthday (for $14)