It really makes things cheaper and efficient, I bought it to connect my HD650 to a balanced amplifier. Works flawlessly. Really worth the price.

Quite a lot of portable devices are designed to deliver 2x the power on balanced output when compared to SE. This adapter is useful for such devices, especially if your IEM / HP can benefit from the extra power. Of course a fully balanced cable is going to be better when compared to such an adapter. However, if you're on a budget and would still like to provide the benefit of extra power to your gear, this could be a good option to consider. I've been using this adapter with FiiO BTR5, Sony NW-ZX507 and FiiO M11Plus LTD for more than a week now. Haven't had any issues in terms of feedback loops or source damage.