I couldn't find the part where it said mentions "sleeveless in summer".

Those sunsmart outfits came out here in Australia when my children were babies.

These days they're recommending we all get a little sunlight to get the Vitamin D that we need from the sun. It all depends on where you live as well. What is suitable here in my zone would not be the same as for someone living in say Iceland. Seeing as we live in the melanoma capital of the world here in sunny Queensland, we have to be really careful. I (fair skinned and blue eyed) grew up in the tropics before there were any sunscreens and awareness. I would never do now what I did then. <shudder>