Because I saw pictures of (Icelandic) sod houses and I thought they were really cool looking.
Example. (square doors.)
If I had to justify it in-game, then I'd say that those houses were built by the original halfling druidic settlers, many generations ago, using magic that let them shape the earth without harming trees. Because with magic, you can build sod houses even when there are trees around and you don't have to deal with any of the negative issues that they normally cause.
When other halflings moved in later, they used other materials.
Again: not a drop of Tolkien. And, of course, I could describe halfling villages in dozens of different ways, so the next one would likely be completely different. Sprawling ranch-homes. Clapboard houses. A repurposed orc fortress. A tent (or yurt) city. Round beehive houses. A flotilla of halfling-piloted houseboats. A halfling tree-village. Neat little country cottages. A village built into the ruins of a human town.
It's really,
really easy to describe halflings and the things they do without referencing JRRT. I'm sorry you can't do it, but maybe you should try practicing instead of just insisting that it's impossible.
