This. We've done that for years. We use one card for groceries, one for gas/auto maintenance, another for on-line purchases, that kind of thing. We pay them in full every month. At the end of the year, we have handy totals for each of our major spending items, and our credit score is through the roof.
In the USA, if you give up your credit card accounts your credit score, strangely, takes a hit. Weird but true, I'm told.
Also, our credit limits have raised repeatedly to the point that we could charge a medium-ranged new car on one of them! Every once in a while a card will tell us what good customers we are and up the limit. I think they're trying to tempt us into buying something we can't pay off all at once!