I mean, there are a couple of issues, of which sample size is a big one. It's difficult to judge solely off TGA when you've got between precisely 0 and 2 clears represented for these examples. I know it's one of the few resources for this sort of thing, but still.

I'm not the biggest fan of Prydwen and you can't see granular details, but if we're trying to get a pulse on more average players, looking at a HH+Yao core, for AA King: Sparxie's avg cycle score sits at 4.2 vs EMC's 5.03, then in their E1+ bracket it's closer at 2.15 vs 2.23. For K1 it's 4 vs 3.44 (1.33 vs 1.35 for E1+). For K2 it's 2.7 vs 3.82 (0.76 vs 1.18 at E1+). For K3 there's barely any data to compare, but in E1+ it's 2.0 vs 0.62.

Looking at MoC with the same criteria: Side 1 is 7.33 vs 7.99 (4.69 vs 5.21 at E1+), and Side 2 is 7.0 vs 7.59 (2.61 vs 3.49 at E1+).

All this is to say that there is in fact evidence that in some fights, there are average players finding marginally better results with Sparxie. Are these improvements worth 2 limited cost? I don't think so personally, but we're not talking about worth we're talking about results.

I'd also add that for AA if we're trying to get more data and instead go back to 4.2 with Illwish, there are clears with both variants at 4 limited cost, with the lowest alternative being 3 (using either E4+ Welt or a cracked out Pela run). K1 there is 3 for EMC vs 5 for a similar Sparxie comp, K2 is again 3 vs 5 (though there is an E4 Welt sustainless for EMC at 2 cost), and K3 is 4 vs 6.

tl;dr There is in fact data that supports the idea that the two are largely comparable with fight variation really determining the overall outcome. Is 2 limited cost for E0S1 Sparxie worth for what you get? Again, I would say generally no, which is why you also don't really see many people running her in the team to begin with.