Are modern clipless shoes and pedals that much better than toe clips and straps? I've recently returned to cycling after a couple of decades, and I'm trying to get familiar with the current gear and components.  

I still use toe clips and straps on the pedals on my 1990 Trek road bike.  But clips and straps are so far out of fashion that you wouldn't even know that they used to be common.  I can hardly find a mention of them anywhere.

Why have the modern pedals and and shoes so completely replaced the old-style clips and straps?  Are they really that big an improvement?
Clipless pedals hold your feet more securely and release easier than toe-straps and clips. As you are probably aware, it is possible to to tighten straps to the point where they must be released before the foot can be removed from the pedal. A properly functioning clipless pedal will always release the riders foot.