From the team announcement:It's a little strange that both CdG and Mitchell are ahead of him, tbf. It's not like he came back into the ODI team and put out middling results. He's averaged 44 with the bat (SR of 107) and 19 with the ball since his comeback. He then followed that up in the Super Smash and did similarly well. It's not like we are the best team in the world with amazing depth, this a number 6 ranked side that's been hit by injuries. And he can't make a squad of 14-15?
“We see both Daryl and Jimmy as important all-rounders in the T20 format. With a travelling squad of just 13 and the need to balance the options for the series, Daryl gets this opportunity against India as a reward for his consistent form for the BLACKCAPS.”
Neesham was selected for NZ A, but from the quote above it appears that he will get some Black Caps white ball action before the World T20.
CdG is being picked as a specialist batsman in T20I so not competing for a spot with Neesham.