Not to mention you're going to be looking at quite a bit of fiddling to get any sort of linux distro playing nicely on it, so from a tooling side, costs will be much higher.
It's also literally 5 times bigger than a pi in a standard enclosure, so enclosure costs and space costs.
Plus, it idles at the same power (~10 watts) that the pi pulls during max load. It maxes out at ~70 watts draw. 10 watts over 5 years = $35. 70 watts over 5 years = $250.
Plus - I refuse to touch celeron with a 20ft pole. They're consistently one of the worst performing processors I've ever had the displeasure of using. You call the pi's hardware old, but the celeron in the model you linked is 5+ years old now, and it's the shittiest of the shitty models that intel sells.
You can hate on the pi all you want - I tend to agree, they're a bit overpriced for what you get at the best of times, and when they're both expensive and hard to get... alternatives are a great option. But that hideous thing is not the alternative you should be suggesting.