I'm sure it's all a matter of what you are used to. I don't have pierced ears, so it never even occurred to me to pierce my daughters' ears.
They are now 10 and 3, and neither has even mentioned the idea of getting pierced ears - again, probably because they don't see me wearing them, so it's a non-issue in our house.
If I had wanted them to have pierced ears, looking back, it probably would have worked with my oldest, as she was a calm sort of child and would have let me keep them clean, etc. My youngest pretty much hates all forms of hygeine, washing her hair and trimming her nails are torture! She has huge tantrums. So I definitely wouldn't have wanted to add cleaning her ear piercings to that list.
We are also a family that frequently loses socks, belts, hair bows, and other accessories, so we'd probably be losing earrings left and right also.
For me, assuming I wanted it done in the first place, it would depend on the type of child I had and whether I wanted to add in the chore of keeping them clean, keeping track of the earrings, etc.