Once you do, her Rock The Boat ability triggers, dealing one damage to each opposing character
A 2/2 with haste isnt nearly as exciting in Commander as this card was in Standard, but Im still a fan of the Robin Hood flavor and the secret archer-reach here (I always assumed because Robin Hood reaches to pick peoples pockets)
This process can be repeated as many times as necessary until you have at least one basic Pokmon
It poops out little dudes to protect itself, it resurrects all your weak creatures (who may have fallen while protecting it), and if you're already in a fairly comfortable position when you cast her, Elspeth closes out the game in no time, turning anything you pick into a highly relevant flying threat
Read all about mulligans, sideboarding and most importantly: How to sequence your turns
And, of course, the cards striking design also contributes to its cool factor