'm a yaoi fangirl, and I've came across a handful of traps (where guy gets down/dirty with a cute shy girl. only to find out it's a dude)

so my question is

are these supposed to be chartered toward straight males? oO
why?

is it better to have the "shock effect" of the trap then to make it a regular old female?

Shemale porn is for men, so yeah, traps are probably a man thing too.
The reason for that, it is an erotic illusion. Only straight men are interested in that stuff.
Gay men like men. Gay men also like Buck Angel. Straight men do not.

Around 21 mins. An interesting clip overall.