Hi razoo,
Glad you started the new thread!
I'll give you my opinions, you can take them for what they are worth...
I believe that anything that you are going trust your life to should be well proven. That means that any tool or object you intend to use should be able to function as you expect when the need arises. That also includes your own ability to use the tool as expected.
For self-defense this applies to any tool from alarm systems, or bludgeons, or edged weapons,... to firearms.
In order to prove this with a firearm tool, the firearm must be used in a similar manner as you expect to use it in an expected situation (or as close as possible). It is very difficult if not impossible to be able to setup a scenario exactly as you might encounter it at a firing range or even in a special firearms training course. The best you can do is try to practice as close to what you might encounter as possible wherever and whenever you can.
How much time, money, and effort you want to put into practice (training) is an individual thing. Naturally, the more training/practice the better you'll be if and when the situation arises, and the better you'll be prepared to save your life.
At minimum, I personally would want to be highly confident that the tool (firearm) will function as expected when needed. I can just imagine someone buying a firearm, loading it, putting it a drawer and feeling much more comfortable knowing the protection was there if necessary. Then, some time later, there are noises in the night... they grab the gun and investigate... a dark shape of a large man lunges toward them... they pull trigger... and the gun goes "click". You don't want to be in that position.
Make sure the tool works as expected. As far as making sure a firearm worked as expected I would want to be able shoot at least 200 consecutive rounds through it with zero malfunctions, using the same ammunition I was going to use for defensive purposes.
Also at a minimum, I would want to be fairly sure I could hit within 1.5" of POI (Point Of Aim) at about 15" during rapid fire under all lighting conditions. This would cover the accuracy necessary in most expected self-defense situations. I would practice as much as necessary to accomplish and maintain this level of accuracy. The amount of practice necessary will of course vary with each individual. BTW, I have found a laser to be extremely helpful in this, but don't make the mistake of totally relying on it - it could fail. Be sure to maintain your proficiency with the iron sights also.
A far as the Kel-Tec P-3AT as a CC weapon for an inexperienced gun owner goes ... I am a prime example. My Kel-Tec P-3AT was my first and is still, after three years, my only gun. I trust it completely to do it's part to help protect me and my loved ones. I also believe, through practice, that I have the skill necessary to complete my part of the equation. So of course I would say that the P-3AT is a good choice.
As far as "fluff and buff " goes... Fluff and buff is just a way to break-in the gun faster. P-3AT's vary in how much it takes to break them in. Some function perfectly from day one, others may take up to 200 rounds or more to smooth out. Rather than wait and use expensive ammo to smooth it out you can pre-smooth certain areas with a little fine sandpaper.
Here's what I suggest ... Clean the gun and lube it thoroughly before you shoot it. Use your snap caps and cycle the slide and trigger as much as possible before your first range visit. You will be surprised how much this alone will smooth out the trigger pull and the slide function. Use the laser during this to help you with your grip and trigger control. I did this for about 250 cycles while watching TV, it was much smoother before I even went to the range, and it saved a lot of ammo.
Take it to the range with a variety of ammo and try it out. See which ammo seems to function best and is the most accurate. Make sure you don't "limp-wrist" while trying it out.
If you don't have any malfunctions during this first session fluff and buff is not necessary. If you have malfunctions some fluff and buff may help. Come back and report your range experiences here and we'll help if you if you have any problems.
As far as care goes... Be sure to visit the range often enough to keep your skill up, and clean and lube it after each range visit.
Hope this helps,
Bobo