Another option is to load the CR2 (Figure) or prop (PP2) into Notepad.
Look for the lines that say...

version
    {
    number 8

...simply change the number to read 4.0. It will usually now load in P4 or P4 Pro Pack without any error messages.

Note I say usually because it doesn't work all the time. As HBorre comments new stuff like Dawn won't. Also if the model uses shaders/materials and not textures, you won't see those displayed on the model.

But good news is V3 and even V4 to some extent can be used OK. Plus generally anything with standard textures works fine and it's incredibly easy to fix many texture problems In P4/PP.  

As for using it why not? Dashed handy if you ever create stuff and want to ensure your model will work in most software. Make it P4 compatiable and it will, no hassles with loading it in studio, vue, max etc. 

Pinky - you left the lens cap of your mind on again.