You forget Happy, the points game is open to everyone, on any scale.
Most players have the money to cover all their expenses and use excess savings to float CC spend, whether it is just signup bonuses or full scale MS.
Some have an extra 100K sitting in a fidelity account just to earn miles. These players don't worry about getting caught short and shudder to think about having to use 0% cards and balance transfers to keep from paying interest.

Some players struggle to pay bills and can barely float the required spend for signup bonuses. Those players are getting the miles and points needed to take vacations that would not be possible otherwise. Whereas most of us can afford to vacation wherever we like, and use this hobby to reduce the cost or upgrade our trips, some players are making something out of nothing, and walk a fine line to do it. I started this way, and thanks to the mint, was able to improve my credit score, stick more into savings, and become a constant player in this game without worries.

Your advise is well intentioned, as the game is not worth playing if you are paying interest and carrying balances. It takes self control and money management skills to keep from getting in the hole when dealing with credit.
I can see how mention of balance transfers would raise concerns, but for some people this is useful tool to keep from paying interest, while keeping enough cash to maintain their monthly bills. Paying a transfer fee to avoid paying interest for a year is the lesser of two evils when it gets to that choice.

I think most people playing the points game know that keeping a good credit score and not carrying balances are the most important keys to success.

Back to topic, our Arrival+ cards are coming up for the first year at the end of the month. I am hopeful due to some of the recent comments that I can get annual fees waived and keep it for a while. I am getting good use out of it as a way to get credit for cabs, limos, and car rentals. Will let you know how it goes.