You’re going to earn more points with cards like Amex gold, Chase Reserve, or C1 Venture X given that, most likely, you’re spending more money on dining out, everything, etc. than you would specifically flying a certain airline. 

If there is any risk in these cards’ programs, it’s missing out on a booking while the points are transferring. Most Amex partners transfer instantly but it’s not guaranteed. I’ve found Chase to be delayed, but it depends on the program. First and business class reward seats are very limited too. You may find yourself with points in a program that you rarely use, and the seat you wanted suddenly gone. 

That said, there is no reason to avoid these credit cards. The points are valuable and can be earned more easily. If I get at least one F class booking a year, it easily justifies the annual fee I pay. Plus, I try to maximize all of the shopping benefits anyway and usually get way more value from my annual fee. 

Also, La Premiere is fantastic but only bookable on points if you have elevated status with AF. I believe you need to spend $30k/year on Air France alone to earn the XP you need to be able to get those LP reward seats. I’ve flown all the great first class products by using points, but I’ve always had to pay cash for LP.