I guess this is on individual's personal choices.
If I am given an LTF card with no joining fee, I might as well have it just so my overall credit limit is sufficiently high (this too will eventually hit a good threshold, so as to not opt for more credit anymore than what is required for my consumption). Other than that, I personally wouldn't get them if there's no absolute reason to keep them. Too many credit cards are surely not for someone like me since I still use only one or two cards in my portfolio, the most.