the point is that HP fire roserade is the same as as a grass-type with flamethrower. this makes it excellent for hitting the types and mons that normally wall the likes of roserade, letting you turn around and get a kill instead of being forced to switch. To put in perspective:
0 SpA Technician Roserade Hidden Power Fire vs. 252 HP / 252 SpD Scizor: 288-340 (83.7 - 98.8%) -- guaranteed 2HKO Witch Techinician
0 SpA Roserade Hidden Power Fire vs. 252 HP / 252 SpD Scizor: 192-228 (55.8 - 66.2%) -- guaranteed 2HKO Without Technician
^Those are without ANY Sp.atk investment, and vs. max defensive scizor (best case scenario for scizor, never actually happening)
vs. Ferrothorn
0 SpA Technician Roserade Hidden Power Fire vs. 252 HP / 252+ SpD Ferrothorn: 204-244 (57.9 - 69.3%) -- guaranteed 2HKO with technician
0 SpA Roserade Hidden Power Fire vs. 252 HP / 252+ SpD Ferrothorn: 136-164 (38.6 - 46.5%) -- guaranteed 3HKO without technician
so yeah, it hits some very popular mons that would otherwise have the potential to wall it hard. and that doesn't even include genesect, which already got calculations earlier from supernut64. With the addition of powder immunity on grass-types, anything that allows you extra advantage against enemy grass is very much worthwhile.
While I don't believe that an all-out attack set or assault vest is the right choice do to having some valuable options in spikes and sleep powder, technician is certainly equal to natural cure, particularly in the world of smogon sims where you can simply nullify jumping through the various hoops of breeding that such things require.
0 SpA Technician Roserade Hidden Power Fire vs. 252 HP / 252 SpD Scizor: 288-340 (83.7 - 98.8%) -- guaranteed 2HKO Witch Techinician
0 SpA Roserade Hidden Power Fire vs. 252 HP / 252 SpD Scizor: 192-228 (55.8 - 66.2%) -- guaranteed 2HKO Without Technician
^Those are without ANY Sp.atk investment, and vs. max defensive scizor (best case scenario for scizor, never actually happening)
vs. Ferrothorn
0 SpA Technician Roserade Hidden Power Fire vs. 252 HP / 252+ SpD Ferrothorn: 204-244 (57.9 - 69.3%) -- guaranteed 2HKO with technician
0 SpA Roserade Hidden Power Fire vs. 252 HP / 252+ SpD Ferrothorn: 136-164 (38.6 - 46.5%) -- guaranteed 3HKO without technician
so yeah, it hits some very popular mons that would otherwise have the potential to wall it hard. and that doesn't even include genesect, which already got calculations earlier from supernut64. With the addition of powder immunity on grass-types, anything that allows you extra advantage against enemy grass is very much worthwhile.
While I don't believe that an all-out attack set or assault vest is the right choice do to having some valuable options in spikes and sleep powder, technician is certainly equal to natural cure, particularly in the world of smogon sims where you can simply nullify jumping through the various hoops of breeding that such things require.