>>19704566The vast majority of good pokemon are dual typed because it gives better offensive and defensive capabilities. Very few pokemon can get away with being mono-typed, unless they have exceptional qualities (see: Clefable.)
Grass is a good defensive typing primarily because it resists water and ground, and is also immune to Spore and Leech Seed. Electric immunity is not bad but a lot of things with Electric STAB also carry HP Ice. Basically everything I listed makes use of their grass typing to handle stuff like Azumarill, Keldeo, Excadrill, Mega Gyarados, etc.
>>19704632No one uses Chlorophyll Tangrowth. All of its sets use Regenerator, either with lefties or Assault Vest. It's balk as fuck and is really annoying.
