Hey, Trese is a good comic book. Also KikoMachine, if you know what I'm talking about. (Go Manix Abrera!) Seriously, Pinoy comics are seriously overrated.
But to the topic at hand...
Comics are pretty much like illustrated books. It's like the culmination of art: pictures and writing to create a seamless experience of pure story. Manga is that. Comics are that.
But honestly, saying that "comics are just combined illustrations"? Really? Come on.
They've never read manga before? Read some kind of Archie comic book or a strip in the newspaper? That's comics, and they're everywhere.
Heck. even books are now being turned into comics, because that's how freakin effective comic books are! They give people a better picture of things!
I'm a novelist, and I'm an avid reader of comics from print and electronic. I know how hard these things are to make. Heck, making a comic is even bloody harder than writing a novel!
(Respect to you peeps making comics.)
But yeah. I'm really amazed how people could think this way.