New receiver...please help me undersatnd why HDMI passthru is even worht my time

Ok, ive looked at the other threads on this and want to ask you this question...

I currently have my 50" plasma mounted on the wall. It is run into my Yamaha HTR 5240.

My receiver doesnt have HDMI so I just use the digital coax for audio (I dont know if the optical is working, ive tried too dif cables) So from my DH box I use HDMI from tv to HD then simply digital coax to receiver..

Why should i get a new receiver just so I can have HDMI passthrough? the video will be the same and that wont help me at all and ill use optical audio...

Is there something im missing? Shoudl I wait or is there another reason im just not seeing?

Im looking at a basic yamaha receiver to repalce it wiht hat has hdmp/pt etc..

Thanks!!!

Beerstalker... thanks for the reply.

One addition is that I am hooking up my dvd player, and my cable HD box to it..things seem to work fine...even if the optical port deosnt seem to work (i think) but Im using digital coax, and its ok...so is it in my best interest just to wait?

Thanks!