cicolin81 -
First of all, welcome to the forum.
Starting out, a bit of advice: you'll get more and better responses to your question if you start a new thread rather than adding on to someone else's. More people will see the subject and respond; by adding what is essentially a new subject to an old thread, people who have already posted in the thread, or those who are not interested in the original thread's subject won't see your request.
The caution to not charge directly from a flask originated with long gun users. It is not unusual for a long gun to retain hot embers in the bore, especially in the breach area. Pouring directly from the flask creates a column of combustible powder from that ember all the way back up to and into the flask. A loaded flask is a bomb in your hand. I have personally seen two incidents (in over 30 years, and thousands of gun loadings) in which a flask was ignited in that manner, and in both cases the result was severe burns.
The situation is not as dangerous with revolvers or short guns, as they tend to cool more quickly and hot embers are quite unusual. Also, we tend to take longer to charge revolvers, giving any embers longer to go cool. However, when one considers the possible consequences (third degree burns on the fingers, wrist, arm and face, and possible loss of an eye) it simply makes no sense to tempt fate. Being safe is the goal; ignoring the physics and saying, "It won't happen to me" is being unsafe.
Here's my opinion about wads/grease: The best, and sufficient, protection against chain fires is the proper size (and shape!) round ball and a properly fitting percussion cap. Thus wads/grease are helpful, but not in and of themselves the full measure of protection. What they are good for, however is lubrication of the chamber and bore. It is true that a good wad/grease will keep fouling soft and allow the gun to be fired several more times before fouling causes binding of the action. I personally prefer lubricated overpowder wads to grease over the chamber just because they're less messy on hot days. But that's a matter of personal choice; grease is allegedly more 'authentic', and that matters to some.