If the player or any mob comes in contact with lava, they will quickly take damage and die, which means it can be useful to protect the player's base from mobs. Most items that fall into lava are incinerated on contact.
Bucket of lava
Mixing lava and water will create cobblestone, which means it can be used to create a cobblestone generator.
If the lava is a source block (the lava block where lava flows out of), then obsidian is created. This same concept can be done if it comes in contact with rain and snow, except these create obsidian with any lava block, not just a source block. This means flowing lava can be used to generate obsidian when it is raining.
- 1.27: The texture of lava was updated