I think its a good strategic decision to extend the ICO in order to accommodate more prospective investors to participate in it given that the crypto market is not quite good right now.
Their sale started 1st of December, so I believe everybody who wanted to invest already invested, pretty much. However, it's true markets are not in their best state right now, but devs could've made an announcement why they decided to postpone the end.
Unfortunately many ICO's struggle with the current bear market, especially the ones where the investment is locked in USD