We know he's the interim SIE CEO, meaning he is only CEO temporally during the transition between CEOs. Jimbo quitted last year, but since these companies do everything per fiscal year, he stays until the end of the fiscal year, also helping to do the transition. And then in the start of the new fiscal year they promote (or hire) the next CEO.
As a bridge, during this transition there's an interim CEO. Someone who in normal conditions manages the transition from a CEO to anoher and normally doesn't make important changes during that period (like to fire 8% of the workforce shutting down an entire studio).
Normally the transition doesn't only is a change of CEO. Normally the new CEO makes also some changes in the vicepresidents, senior vice presidents, people in charge of some subsidiaries etc. to build a team he's comfortable with. The interim CEO also takes part in that process.
As an example if the next CEO is Eric Lempel they'll have to replace him as SVP of marketing promoting someone else there, and that person also with another one etc. And maybe he decides to replace someone like Hermen, or other vice presidents etc.
Pretty likely they already did part of this process and the next CEO will start working April 1, but sometimes it takes a few weeks. I assume Totoki won't be there a month.