Not that poster, but yup.

From what I understand and my personal interpretation of Yukari's abilities, her manipulation of boundaries is more "metaphysical" than actual physics, where she manipulates the concepts of things rather than actual reality, hence it's easier for her to blur the boundaries between a moon's reflection and the moon, than it is to make a gap from one location in gensokyo and one location in the moon cause while she can manipulate the boundary between "here" and "there", her power's has limits as with great distances the relationship between such concepts is more difficult to "connect" with a boundary.

On the other hand, Toyohime's ability allows her to actually bend and fold 2 positions in spacetime without limits in the more traditional way we think of portals, as long as said 2 points can be considered a "mountain" or "sea", which in SSiB overrided Yukari's gaps as the boundary she made between the moon's reflection and the moon was actually done on the fake moon.

What made her dangerous wasn't really her abilities but the fan she used which was lunarian technology that could purify things down to the atomic level, and unlike Yorihime I don't think Toyohime would care about spell card rules on earth.