bio tracker is more useful than you might think, it helps you find out where the enemies are during harder stealth sections, and with that you can coordinate better with your team to wipe an entire room which would seem impossible. Also, it works when the enemies are moving around so that you can ping them making standing your ground, knowing when to back up, and kiting much easier. Even if you don't use the bio tracker that much it has another advantage, it saves tool refill, so rather than having less mines, c-foam, and sentry ammo, you can have more of each and make most alarms a cake walk. Not bringing bio-tracker can hinder you a lot, especially in harder levels where there are more enemies in a room and tools are needed more than ever.