This may be old news for some, but perhaps not others:
You can, for instance, use it to find Greek or Hebrew words that translate each other in the LXX
Search a morph-tagged LXX for the first lemma WITHIN 0 WORDS of the 2nd lemma.
For instance, <Lemma = lbs/he/אוֹ> WITHIN 0 WORDS <Lemma = lbs/el/καί> in the Septuagint with Logos Morphology, will give you all the hits in which אוֹ is translated καί.
The other way is to run a Bible Word Study starting from the Hebrew Lemma and under translation, change the Bible version to a LXX. Then you can click on the translation you are looking for in the pie chart to see a list of the corresponding verses. However, the search above gives much greater flexibility and can be exported to a Passage List.
You can also, for instance find all the times the word "Lord" refers to the person "God".
<Lemma = lbs/el/κύριος> WITHIN 0 WORDS <Person God>
You get the picture. It allows you to combine different attributes (and theoretically even more than just two).