I personally think it's just like any tool - useful in select circumstances and only if used the right way. 😉   In a list of results, IMHO the information that's in the subtitle will only be useful if it tells people something that they don't already know or can't assume, and is of greater benefit to them one way or another.

x2. It seems like something to help get the buyer to click on the listing but for $2, that can be costly over alot of listings if the subtitle isn't working. Extra information can be in the description instead of the subtitle.

The pricey things seem worthwhile when the item will guaranteed sell well above the cost of any extra feature.