Laptops predate cell phones in mainstream use. When laptops started, there were a variety of battery types in use with no standard charging voltage so Wh was the fair way to compare.
Cell phones have pretty much always been 3.7v lithium so mAh is a fair comparison and gives a bigger number than Wh.
3000 mAh * 3.7V = 11.100 mWh
Much bigger. Much better.
I hate mAh… it’s absolutely no information how much energy is inside without taking the voltage into account. If you use directly (m)Wh, you directly have the amount of energy the battery can contain.
The thing is, batteries are measured in Ah, and not Wh. That's because their voltage changes all the time, and is mostly the same for the same kind of chemistry, and also because for most of their uses, the current is the actually useful information.
Phones are just using the standard metric. It's laptops that are weird.
They both tell the same story, but one requires extra information you don't have. You don't say that the latest i3 pulls 6 Amps, you say it pulls 65 Watts. Also the voltage does change as the battery discharges, that's why you use the nominal voltage of the pack. mAh is also not a current
I think you misunderstand nominal voltage and fully charged voltage. 3.7v is the nominal voltage for a lipo battery. 4.2v is the standard fully charged voltage. However, phone batteries are rated at 4.3v.