The original doesnt have any good grass types as most of them are stone only in which the way to get stones in these games is stupid. Tangrowth is a fine choice but tangela is super spdef frail and super slow which means it dies to almost any special attacker, while bayleef is tankier on that while still having decent physical bulk. Tangrowth still is awful spdef wise and slow so its only useful vs physical attackers, while meganium can handle them decently and is faster.I was saying edgy in " Oh, I'm sooo quirky, I chose chickorita, " and yeah, there is a geat replacment to it in tangrowth in HGSS because it fills basically the same rle, and I think theres some other good stuff in the original things.
They both have a similar niche but in game i think bayleef is better as an overall defensive tank while tangrowth is better as a physical attacker and physical tank. Either is fine, theyre both usable



 