Being able to prevent damage to your creatures is good, and its even better when your commander has mana sinks built into them
In Giselas case, thats double damage for any source damaging opponents or their permanents, and incoming sources of damage halving, rounded up
A turn 5 play on turn 4 is nice, but a turn 4 play on turn 3 is still a big deal in its own right
Either as a last-ditch protection spell on defense or a finisher on offense, being able to windmill slam this for zero mana was certainly a huge play
Ain't no spotlight in town that ain't eyein' Kitt, and she dang glows in 'em
Its still great with Siege-Gang Commander, but no one cares about a 2/2 haste, and most of your Goblins dont benefit all that much from cost reduction or haste