Well now the most expensive - Undercity Sewers - is up to $25 and half the cycle is over $10
Perhaps the best way to think about Damping Sphere against Storm is as a slightly worse Rule of Law that limits players to two spells each turn rather than just one (for example, with a Damping Sphere on the battlefield, Storm will likely still be able to cast two cantrips like Serum Visions or Sleight of Hand in the same turn but shouldn't be able to afford the third)
Many of these creatures have powerful secondary abilities including creating additional creature tokens (Bladewing, Death Tyrant, Feldon, Kari Zev, Krenko, Mardu Strike leader), drain/life loss (Calculating Lich, Hellrider), direct damage (Combustible Gearhulk, Dreadhorde Butcher), anthem/buff effects for your army (Drana), card draw/free spells (Etali, Florian, Garna), additional combat step (Moraug), and many more
Also, a 2/1 for two mana isn't very good when we'd rather be playing our commander on turn two
It does not cause any damage