Yes that will work. The reason for the separation is that “rental” and “property” are completely different in requirements. eg Price.
You can add land as an option using a filter to edit the list of property types in your functions.php file of your theme or in a little plugin.
https://easypropertylistings.com.au/docs/modify-listing-categories-filters/
The thing is that buyers who look to purchase “land” are often not looking to purchase a “house”, same as people looking to buy a house are not also looking to rent, or to build.
The plugin allows you to better configure your site for your users, further enhancing your offering.
So you can have a complete section about purchasing land, another about buying exsisting property, and another about renting. This is better for users, and search engine results.