I used to like choosing what the dses wore, when they were little. And I did like what they wore to 'go' together - dh was not bothered by this, and to be fair, I am not sure why it mattered to me that their socks matched their shirt or whatever - but it did matter a bit, and I don't think it did any harm.
Their clothes were picked primarily for comfort and practicality, so whatever they wore, they could run, climb, play in - and if it looked nice too, that was a little benefit for me.
I think it was partly because, as someone who's very overweight, it was hard (and expensive) for me to feel I looked nice, but it cost much less to give the boys nice clothes.
And the time when you can chose what your children wear passes like a flash, and they get, and can express, opinions of their own. I now have an 18-year-old, a 20-year-old and a 22-year-old - and they all have very different senses of style.
The eldest likes tweed, brogues, expensive shirts and wool jumpers - he is a stylish grandad, basically. No2 lives in sports gear, though he has been known to go to the supermarket in a santa onsie, with bright royal blue nylon shorts (long, baggy ones) over the top. The 18-year-old likes labels, skinny jeans and looking cool.