For the sake of stopping this argument quicker since it somehow angers me the more I read it:
I will go ahead and point out that Yuugi does seem to actively use a power related to her ability in some of her spell cards (the brute force unrelated ones), although as stated before, what it actually does is unknown since the spell cards themselves, which so far I've found to be Oni Sign "Dreadful Raging Waves" and Big Four Arcanum "Knock Out in Three Steps", are noted in respectively Double Spoiler and The Grimoire of Marisa to work by a power or technique that can't be understood.
Therefore, it might be best to think of Yuugi's ability as exactly how it's translated plus the metaphor, "having unexplainable phenomena". She does not manipulate them, especially since unexplainable phenomena in this case are seriously unexplainable by all means, but she appears to use them and as they are unexplainable even by Gensokyo's standards, she can (presumably) not use magic, control youkai, etc. This would mean "wields" is also correct. Again, "manipulates" or "power to the extent of" would not be correct in translation or for the actual ability, so the definition of Yuugi's ability is probably more precise than we think it is.
EDIT: Actually, for obvious reasons plus Yuugi does summon spirits in some of her nonspells, "anomalies, strength, disorder, and spirits" in and of itself would probably make sense.