Really, to what extent that methods used to promote Buddhism is inappropriate? Manga and anime is in reality just another medium, another platform. If it can be used to express Dharmic intentions, why not? It is just like how the culture of the countries that Buddhism set foot in were used by Buddhism to spread the Dharma to them. So, is this not like the same as that? It is just a different medium in which the Dharma can spread from. Personally, I also grew up with the manga culture, and I dont really see too much of a problem with using anime and manga to promote Buddhism or to attract those who would normally not be able to listen to Buddhism to that direction. It is just a method at the end. If we should not have a fixed view of how Buddhism should be and how the Dharma would spread, then why do we feel upset when we look at something like that?
Toro Benten is probably a reference to and was inspired by Benzaiten or, better known to us as Sarasawati. To be honest I was very shocked at first to find a temple 'selling' Buddhism in this way, but upon further thinking, I realize it was more or less due to my closed mind that I was unable to accept such a method. The last part where Toro Benten and the other mascot reveal their breasts is, a little, unnerving in more ways than one, tho.