Wes, yes, it has been useful. But the MCPE update from 0.9 to 0.10 was strictly bug fixes. So INV didn't need an update. The only way to know for sure whether or not the app has been abandoned is to wait until at least 2-3 weeks after 0.11 comes out. And I do mean "at least". There are rare occasions where similar apps take longer than that.
INV Editor does still work to an extent. I've been working on a few maps lately, and it has come in handy. But 0.11 still has a number of new features INV currently doesn't recognize, for example, fishing poles. And earlier today, it crashed, tried to reload, and immediately crashed again. Twice in a row, definitely not good. My screen was idle when it happened, so I'm pretty sure it's not a system problem. Dev, if you're reading this, at least let us know whether or not you're currently working on it. We've been asking about an update since day 1 of 0.11's release.
Two things I'd like to mention here. First, and most importantly, the 0.11.1 compatibility update was released yesterday. So for those map makers who have relied on INV Editor in the past, it's now ready to use.
The next thing I want to give out is a feature suggestion, and there's a chance I might have mentioned it before. I think the Pro version could do with a map compressor/extractor. Instead of trying to find an app that will zip that custom house you want to share, or open that mini game you and your friends want to play together, INV would have the ability to do that for you.
Will there be a version compatible with the 0.12.1 beta?
Remember when it took forever from 0.11.1 release to INV being updated for support? Chances are, if there becomes a beta for 12 compatibility, we'll probably see the final version shortly after 12's release.