First separate format from leaf grade
A tea bag, loose-leaf pouch, pyramid sachet or compressed cake describes how tea is packaged or portioned. Whole leaf, broken leaf, fannings, dust and tip-rich grades describe the physical character of the tea itself.
Those ideas overlap, but they are not the same. A bag can contain excellent whole leaf, and loose tea can be low grade. The useful question is what leaf is inside, how much room it has to infuse, and whether the format suits the way you want to brew.