When we talk about a 'stablecoin', we usually mean a coin that is stable relative to something we care about. In the case of most stablecoins, they care about being stable to the dollar. More specifically they aim to be worth exactly $1.
FLOAT is fundamentally different. It aims to have low short term volatility, allowing it to be practically used as a unit of account (for comparison's sake alone, bitcoin's volatility famously made even buying a pizza meme-worthy). However, over the long term FLOAT's value should change according to its own demand and the demand for the underline cryptocurrencies in its “basket”. As such, FLOAT's value should gradually change as crypto is more or less valuable and, as a result, protect the purchasing power of users in the long-run.