Honestly, I don't think you can play Star Wars Saga without them. The initial problem is that classes with fun powers are fun to play, and especially attractive to beginners. Whether it's spells or uncanny dodge, you need to know exactly how it works. When I play a mage, I already keep a sheet of paper with all of the spells and all needed details -- how is that different from cards? Anything that keeps the game moving and flowing easily is good, (vs. stopping while someone looks up a paragraph on page 211 that says you can't use the power quite that way, which devolves into a rules argument). Cards might not ENTIRELY prevent that, but they would help. So... Power & Spell cards? I'm for 'em!
Especially when they are that pretty. Mine had no pictures, just names, stats, effects, and the relevant rules from the relevant handbook. Those are TFG, Pjotr.