Credit card fraud

I got a call from my  credit card provider.  They were questioning certain transactions  made in California last month: to wit,  a charge for gas at a Shell station, and a purchase from In n Out Burger.  The two together were less than $50, but the bank was right.  I was not in California at the time.
Neither was my credit card.  It was secure in my wallet.

So  somebody  committed a felony to get some gas and a burger. I'm struck by the modesty of their desires.  Why not buy an expensive camera or  a set of tires?  (These are the items a thief bought on my credit card last time I was robbed.)  Why would anyone risk getting a criminal record for a hamburger?  If I were going to steal something, or defraud someone, it would have to be for a much larger sum than that.

Update:  I am reliably informed that the modest first purchases are just a trial to see if anyone notices their card is missing.  If these go through, they know you or your bank are not paying attention and then they can really let themselves go.