There are several reasons for this and they have historically spanned all iterations of aggressive blue decks
The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, and vigilance

$2.29 Smuggler's Copter (0062 - The Strahl) Final Fantasy Through the Ages $8.99 Mizzix's Mastery (0041 - Dawn Warriors' Legacy) Final Fantasy Through the Ages $2.29 Teferi, Mage of Zhalfir (0032 - Edea Kramer) Final Fantasy Through the Ages $4.49 Mangara, the Diplomat (0025 - Minwu, Rebellion Strategist) Final Fantasy Through the Ages $3.99 K'rrik, Son of Yawgmoth (0036 - Emet-Selch, Ascian) Final Fantasy Through the Ages $3.99 Bruse Tarl, Boorish Herder (0050 - Hugo Kupka) Final Fantasy Through the Ages $4.49 Winota, Joiner of Forces (0019 - Bartz Klauser) Final Fantasy Through the Ages $9.49 Cryptic Command (0029 - To the Crystal Tower) Final Fantasy Through the Ages $8.49 Loran of the Third Path (0024 - Garnet Til Alexandros 17th) Final Fantasy Through the Ages $5.49 Varragoth, Bloodsky Sire (0037 - Ardyn Izunia) Final Fantasy Through the Ages $3.99 Carpet of Flowers (0044 - Fal'Cie Paradise) Final Fantasy Through the Ages $3.49 Kraum, Ludevic's Opus (0056 - Barnabas Tharmr) Final Fantasy Through the Ages 0 results found

Players who pick up this set will focus on doing just that, having massive creatures beat the everloving heck out of one another on the tabletop
Training Grounds, Gilder Bairn, and Seedborn Muse are great enablers, and it's almost trivially easy to get infinite mana and/or counters, if that's your thing
Its second ability makes a great mana dump in the latter half of EDH games: The conditional modified attacker stipulation is easy enough to satisfy, so 5 mana for a 5/5 flier is a great price