The relevant research paper doesn't address the question as to whether or not pornography increases sexual performance in women. Sommet and Berent (2022) found a correlation:
In contrast, among women, higher and increasing frequencies of porn use were associated with higher levels of sexual self-competence, improved sexual functioning, and enhanced partner-reported sexual satisfaction (for some aspects).
Porn use and men’s and women’s sexual performance: evidence from a large longitudinal sample; see also this survey data.
The paper doesn't claim that porn does (or doesn't) improve women's sexual performance. In fact, they spend a paragraph warning the reader about the correlation vs. causation problem:
Third, observational data cannot be used to draw causal inferences. However, we believe that causality should be assessed in
terms of a ‘continuum of plausibility’ (Dunning, 2008) along
which longitudinal evidence is located above cross-sectional evidence (but below experimental evidence; see also Grosz, Rohrer,
& Thoemmes, 2020). In our case, given the consistencies between
the results from the fixed-effects (focusing on within-participants
change) and first-difference (focused on wave-to-wave change)
regressions, we believe that causality is at least plausible. That
being said, two alternative explanations – which we regard as
less parsimonious in the case of a reversed interaction (for a
related discussion, see Wright, 2021b) – cannot be formally
excluded: (i) the presence of unobserved time-varying confounders (e.g. variations in well-being; see Kohut & Štulhofer, 2018)
and (ii) reciprocal effects (e.g. for men, a decrease in sexual self-competence can cause an increase in porn use, and for women,
the reverse could be true).