In professional games to easily seen in stealth, stealth wont last long enough for you to reach the enemy, your so slow that the enemy can effectively walk backwards faster while shooting at you then you can run and hit him with your sword. phantom can no longer 1 shot all medics.
Not all of his loadouts are katanas, none of them have attack speed, and all of the katana loadouts are garbage without melee damage because his katana damage doesn’t one shot medics and objective specialists.
The only thing phantom has is positioning with his stealth, and how is that effective when they have a vasil sniper?
Knife would have the same amount of damage or probably higher if you run proxy with attack speed perk.