Opinions: Using Lucene as a thin database

[Kevin L. Cobb]

I use Lucene as a legitimate search engine which is cool. But, I am also
using it as a simple database too. I build an index with a couple of
keyword fields that allows me to retrieve values based on exact matches
in those fields. This is all I need to do so it works just fine for my
needs. I also love the speed. The index is small enough that it is
wicked fast. Was wondering if anyone out there was doing the same of it
there are any dissenting opinions on using Lucene for this purpose.