it makes it look like your using a hubble space telescope RC optics, and gives it the classical hubble picture look!
so when you show the people that dont know anything about astronomy, they think you image from a full scale size observatory!
infact i think that they draw attention on star's, like if you use them on single star double star and open star clusters they kind of have the effect of drawing attention to the subject, well thats what i think anyway, not that ive took any yet, by looking at pictures with them!