I'd tread very carefully with this.
You're "getting new updates" sure, but the question you need to ask is "so?" Just because software is installing, that's a world away from it actually patching anything beneficial.
You're not tricking MS into giving you patches that they have but don't want to give you out of petulance; rather, you're tricking your copy of XP into accepting patches intended for a different OS. XP Embedded is "mostly XP" in the same way that Windows Server 2003 shares the same core as XP. But they aren't the same.
So if you install patches for XP Embedded (or, looking at the screenshot there, patches for Server 2003 ) then one of three things is going to happen:
1) You benefit from a security update which is relevant to your OS as it patches code common between both systems. Hurrah!
2) Nothing at all, as you're patching a component which doesn't exist on XP.
3) You patch something which is superficially common to both systems but implemented differently, and cause stability issues or worse.
There's every chance that you'll get away with applying these patches, and there's a chance that you might even benefit from some of them. But I'd hazard that there's a very real chance that maybe tomorrow, or next month, or in a year's time, you'll apply something which will completely hose your system. Or more likely, you'll suffer from cumulative damage as you install more and more code that doesn't belong on there and you'll be dogged with weird ephemeral problems that you can't quite put your finger on.
If you're going to follow the advice on that hack then I'd suggest only installing selected updates that you know are relevant and beneficial rather than blindly applying them all, and I'm not sure as that's a call I'd want to make for an unsupported OS on a per-patch basis. I'd also suggest only doing it on systems that you're prepared to lose if they explode, and then of course you've got to argue that if you're prepared to lose that box then why are you worrying about patching it in the first place?
TL;DR - is 'experimental' patching or not patching the bigger risk here? I think on balance I'd leave it alone. Shove Windows 7 or Linux on if you're that concerned.