That may be true of many items, but there is absolutely no substitute for handling a garment or home decor fabric, color matching the necessary accessories such as threads and zippers, and examining all of them before buying—other than plain muslin. Even there, some bolts can come woven off-square and require wasteful adjustments to make the warp and weft line up properly at 90 degree angles.
You are absolutely correct. I am going by my wife and her needle art friends. They get most of their supplies online they love going to a store but the convenience of online is hard to beat.