Retail disc loading?

[Hykem]

Just wondering, why would it require such files rather than just doing it however an actual PS3 does it (perhaps requiring the user to copy and paste the required keys from that wiki site if they can't be included in the package)?

Unfortunately, it's not that simple. Retail discs employ an additional encryption layer on each sector (that's why the .ird files would be needed).
You can see the entire file structure (e.g.: PS3_GAME) when you load your disc on a BD-ROM drive, but if you try to open the game's main executable (EBOOT.BIN) with an hex editor you will see that it's all scrambled (the file's data should begin with SCE).
The algorithm is known and it's possible to decrypt each sector, but we're still studying viable ways to process this (we can't simply decrypt the disc in place or copy it's contents to a user's HDD, so we must decrypt and load each sector on the fly).

I can imagine that players wouldn't mind to sacrify some hdd space if it would mean that the emulator does all the dirty job for them automatically.

I guess, but some games are huge! You could easily eat up to 200GB of your HDD just by loading 4 or 5 games.

Maybe make it that way only one game would load decrypted on hdd at the time? And after playing, players would be asked if they want to keep it on hdd for later use, or free up the space for different game? Well, I am trying to offer another view on this issue assuming it would greatly decrease performance of emulator if it must decrypt the game on the fly, if decrypting on the fly doesn't have any negative effects on performance, then by all means go that way.

For beta testing, sure. I'll probably have to use the HDD in the beginning, but the preferred goal will be the on the fly loading.
After improving RPCS3's virtual file system we will be able to do this with very little performance costs.