There's more to eBay Express than that. For the first time, you'll be able to place items you buy on eBay from multiple sellers into a basket and pay for it all at once. Sellers are required to accept PayPal and buyers are required to pay with PayPal. PayPal distributes the funds amongst the multiple sellers.
I used to work for eBay and I have been a PowerSeller before on two separate accounts at two separate times. The company I work for now sends me to eBay Live! every year. Last year my boss says, "Stu, become a PowerSeller so we can have more credibility at eBay Live!" So I did.
Anyway, regarding sellers bidding on their own auctions... eBay has pretty good software that can sniff out sellers who do that. You can get away with it for a while, but if you're a longtime eBay resident, there's no way you'd risk your reputation by doing something like that. The serious eBay sellers are fanatic about their online reputations.
As a buyer, I RARELY buy on eBay. The occasional deck of cards or something else that is hard to screw up the sale of. I never buy electronics or anything really expensive and fragile. I've heard too many horror stories from my days as an eBay employee.
And heck, I may as well share this. This is me with Pierre Omidyar (eBay founder) and Meg Whitman (CEO) back in 2001 when I used to work for them:
If only I didn't get fired and lose my 1,000 free shares of eBay stock. They'd be worth over $130,000 today.