1.) You get some shoulder/arm coverage without adding too much warmth! I've become a little crazy about showing my arms these days, but I'm working on it! I just feel more comfortable with a cover or a cardigan of some sort. Until I get my summer arms under control, I'll go for the lace cardi option.
2.) Butt coverage. Same thing! I have a large backside. No bragging here though, it's not exactly large in the bubble butt way, but in the way that a barge is large. Okay, I kid. Not that big. Regardless, I love the comfort these guys give. It's lacy and attractive but still lets you cover up a bit. The best of both worlds!
Mine is Forever 21 from last year, but I've linked some similar ones (including plus size options, yay!) Isla's embroidered shirt is from Mexico, but her shorts and shoes are linked below!