You would usually buy it to preserve your purchasing power.

You can hold Bitcoin , but it can decrease in price, so what do you do to not lose money? You buy USDT or sell for other USD stable coins. But those coins are coupled to the USD, which loses value due to inflation. Here AMPL enters the spotlight. By fixing its target price to the purchasing of one USD in 2019 you theoretically won't lose money. AMPL is a coin that should be valued by it's market cap, not it's per coin value. When the market cap grows you are making money.

Currently what drives many investors is that the price of AMPL is 3$. That means the supply needs to triple in the next weeks to achieve the target price. You can buy AMPL and by holding it you get a huge ROI as long as the price stays more or less around 3$ and the buy pressure continues, which is probably will for some time, since the market cap is still "only" around 100M.

For example I received around 20% of the tokens that I held additionally yesterday. (E.g. you hold 10 AMPL and received 2 AMPL from the rebase)
As long as you sell at the correct time you can make huge profits.