What are plausible reasons for aquatic axolotl-like animals to walk on land?

In my world the resident humanoids evolve from beaver sized aquatic axolotls.The only land on the planet can be considered mountainous terrain. Imagine a volcanic crater where only the rim surfaces. Eventually after thousands of years of living in colonies of floating seaweed huts they begin moving onto land (while retaining the ability to live underwater essentially becoming amphibeans). For reference this is what an axolotl looks like-

Why would a creature like this evolve to walk bipedally on land after thousands of years of the species living solely aquatically?

posted over 5 years ago

SlothsAndMe‭

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