But bellsprout, why bellsprout Why not Shroomish Seedot Budew bounsweet oddish I guess bellsprout is fun
Don't you talk smack about bellsprout, mate.
Seedot? That's a peasant until it becomes shiftry and even then it's so TM dependent that you might as have just given up on being in the battle team in your first year. Freaking scrub tier. Roserade? Same deal. No early powerBoth of them are deader weight than pikachu, and don't get me started about how right Lance was. (An ass, but he's right). Shroomish? Breloom might be good, but seriously, shroomish itself is bad. Effect spore is okay but that's the worst ability for breloom. Oddish and all it's evolution are too slow and don't have enough bulk to be effective. With "someone" around the battle team using flying types, you can't move second or you are out cold. Bounsweet is so useless till Tsareena that we may as well just write it off now.
Proof? Look at their offense numbers
Bounsweet: 30/30 (60)
Seedot: 40/30 (70)
Shroomish: 40/40 (80)
Budew: 35/50 (85)
Oddish: 50/75 (125)
BELLSPROUT: 75/70 (145!)
TL;DR be thankful for bellsprout: it is your god and master.