Just because it has fewer parts? Because Glockfanboiz say so? Junk striker fire is as unreliable as junk hammer fire. Any pistol can have FTF, FTE. Most can be made to fail if you limp wrist it (including Glocks). I don't own a Glock that has never had a malfunction on the line even if it was ammunition related or whatever. People on the internet who say their Glock has never failed to go bang don't shoot thousands and thousands of rounds, and probably aren't very good with it to begin with. No pistol is perfect. It is made by men. They all break.
A hammer allows for a single action trigger. I know of only one Walther that is single action striker fire (and it didn’t sell well). The rest are all double action even if the striker is put partially into battery by the action of the slide. You are still pulling back the striker when you pull the trigger. The best possible trigger job on a striker fire is still mushy, slack crap to me.
Now, clearly you can learn to shoot it, and become great with it. It's not any different than bench rest and PRS. You don't need a ton of accuracy to shoot defensively or to play IDPA. You don't see many people running a striker in bulls eye, because they're not very accurate, but you do see hammer guns in IDPA (though Glocks rule).
I probably have fifty handguns. 90% are hammer fire, and none are unreliable. This is pure marketing that a striker is any more reliable. It's mainly because Glocks are simple and well made that people think this.
I have five Glocks, and one of my 17s has a full Ghost Trigger rebuild. It's vastly superior to factory, but it still completely sucks compared to the FNX simply for the fact that it's double action. Now, the FNX isn't a Loaded Springer or a Gold Cup, with a trigger that breaks like a glass rod, but just the fact that it's a true single action makes it feel vastly superior.
Lots of people don't give a damn, and are fine with a sloppy, slack, mushy trigger, and can shoot the hell out of it. I can certainly shoot it too, but I shoot a SA pistol much better. It's no different than DA on a revolver, and cocking the hammer to shoot SA. Does it matter? Maybe, maybe not.
On a giant duty pistol like the FNX, which started as a military contract that wasn't picked up, I think they wanted SA and a hammer because it was probably going to be carried by people who were actually going to use it as a primary weapon (and might need to hit a target at distance) rather than a sidearm or for purely defensive use. At least that's what makes sense to me. I would not have purchased it if it was striker fire. I'd just have gotten another Glock.
I bought mine because I drew out a Government M I wanted to have built for me. I slid my paper across the table to the gunsmith with all the features I wanted listed on it. He looked it over, smiled at me, and slid the paper back to me and said, "FN makes it".