Before the T20 WC last year, the whole squad had played the National T20 Cup and got acclimatised to T20 cricket (NZ leaving instead of playing 5 ODIs was a blessing in disguise in that regard
).
This time we'll arrive to the match against India with zero T20 practice. Three ODIs vs the Netherlands are our preparation.
It can be argued that Asia Cup is the preparation for the T20 WC, and we'll be prepared for the WC match against India, but if we show up unprepared to the Asia Cup and lose twice to India, it won't be a good start on the road to the World Cup.