Sure it's a gamble. But since they have the money and 2 other "reliable" drivers (I put it in " " cause of Latvala), it's not such a big one. As Tommi said it will definitely give PR for both wins and crashes.
Imo the most "risky" part is that they prbly alienated Lappi, which could turn into a Ogier-Citroen kind of situation. When Lappi would not really want to go back to Toyota in 3-5 years even when it's the most logical option like Ogier did with Citroen before 2017 and 2018.