Thank you for your Question.
Mahrams can see you without hijab and you are “free” of outside covering in-front of them. However this does not mean that the modesty and ethics that demands a mother or daughter to observe infront of her son or father respectively to be compromised.
This kind of clothing should be ok for a wife to wear in presence of her husband as their closeness is different than the closeness that a daughter or mother has with her father or son.
During hot weather, cool clothes have proven to be of use and help.
InshaAllah that this helps.