The P99, PPS, and several other newer guns (Glocks, XDs, M&Ps) are all designed without external safeties. That does not mean that they do not have safeties at all though. In all of these cases, they have several internal safeties and are designed to do two things. First, they are designed so that they will not fire if you do not pull the trigger (whether you drop them, smack the gun, ...) and sencond, if you pull the trigger, they will fire everytime. That is why much of the advice you have been given is to not pull the trigger, it is the only way to fire the gun. Many of the older designs do not have features like this and could fire accidentily (though it was still very unlikely) so they would add an external safety. In my mind, I would rather have a gun that is always ready and always safe than one that is only protected form accidents while the external safety is on.
Just my two cents, if you decide that you want a gun with an external safety there are many fine options (Sigs and HKs come to mind).
Jeff