I think ammunition is because when a player dies ammo falls from them more than HP packs and it usually doesn't disappear so I guess if you just want to have a mobile HP pack in a domination 1v1 room that's a use but other than that it's not as effective in Vip maps, and capture the flag.

I think all have some use if you use them correctly:

• Health pack is great for, well, healing
• ammunition is great for people who live a long time / use weapons that all but require it
• Shield/Rage are great when you want to fight against a bigger group.
• C4 is great for quickly blowing up an area (I love using on flag maps to blow up the ground)
• Mines are great for keeping people from crowding in 1 place
• Shelter is almost necessary to defuse mines, but also great for surprise attacks

While people do not seem to take advantage of the fact, do not forget it is possible to switch perks during a round. On certain maps / against certain players, I'll use one perk at the beginning of a round before switching to a different one.

I like how i clicked shield in place for shelter perk....old times.