As to the school of thought that having more credentials &/or equipment is always an advantage, here's a 'devil's advocate' viewpoint: some carriers will 'hold' such drivers/trucks [without the drive's knowledge] against the possibility of needing them for a customer. It's great if such a customer materializes, but if not, the driver has lost out on other loads they might have wanted to run.
I'm positive that having a FAST card was a mistake with one carrier, because they paid more for every mile, Canada or not. Many good loads to points south went to other drivers, while I waited [unknowingly] for someone to ship a FAST load. It made perfect sense for the carrier, who paid the other drivers less than me for the same load to, say, N Carolina, but it didn't work so well for me.