It's not at all unusual, even five years ago I did a USB stick design with 1.2, 1.8, 3.3 and 5V domains, and there were actually two 3.3V domains as it was mixed signal. Five regulators in one USB stick!
Thankfully chips with multiple power domains are increasingly incorporating on chip regulators, but often they're linear so for battery powered stuff it's sometimes necessary to provide an SMPS.
For battery powered stuff, prolonging battery life is a key product differentiator so as part of the design, innevitably lower voltage devices are often chosen.
Frequently particularly on modern digital devices the operating voltage range is fairly wide, so operating at a lower voltage than, say, 3.3V, is part of the give and take of the engineering design. For example I'm working on an ARM Cortex M4 based design at 2.5V simply because that's the lowest voltage I can get away with with all the devices on that power domain, and therfore the lowest power consumption and longest battery life. If it was a USB bus powered device, I'd almost certainly be running it at 3.3V.