We still use them, its too cold here not too, especially at night. When they were little we used the ones with the clips in the crotch, actually they werent even singlet style just thinner body suits without legs and short arms lol. Now we use the bonds singlets if they fit over boofs head, or the big boy singlets from the big boy section with the muscley looking guy on the tag... yep super helpful here.

ETA We stopped with the crotch clipped ones when they started toilet training or in the eldests case got to tall.