With single head drums, the sound goes out of the drum right away. It makes for a very punchy, short sound. On a double headed drum, the sound bounces around, which makes it a longer tone, and because the bottom head has it's own frequency the sound is much, much more complicated than on a single headed drum. Because it's a simpler sound, single head toms tend to be a bit boring when you only have, say, one rack tom and they are usually better used in groups.
When I started in the late 60's, single head toms were the rage. Hal Blaine reportedly got A.F. Blaemire to make him a set of what was called "melodic" toms. Hal gave a set of multi-toms to Ringo. The Ludwig companies came out with multi toms kits that were expensive - but cheaper than if the had bottom heads. Recording engineers got into a habit of using a separate Sennheiser MD421 mic stuffed in the bottom of every tom and that combination is what you hear on tons and tons of the recordings of the era. The Hawaii-50 theme for example.
The whole thing was popular until the mid 70's. At that point, Steve Gadd came on the scene using a 10" double headed tom as his first tom and the single head thing faded.
Also, single head toms nest inside each other for transport and of course they are cheaper to make 'cause there's less parts and that makes them lighter too.
Single headed toms get kinda boring after awhile, sound absolutely horrible, in my opinion, on jazz sets except maybe for latin stuff, and work best when you have lots - 4 or more, preferably 6 or 8.
But you can't get the single head tom thing without looking at how they were recorded because that's 1/2 of why they were popular.