It's a tradeoff someone down the chain is making, LPDDR3 has a max of 16G and LPDDR4 is not supported on skylake/kabylake.

LPDDR3 being 30% less power drawing than standard DDR4.

So. More ram or more battery..

However I have a personal vendetta against Lenovo for their absolutely abhorrent practices in terms of consumer safety and their declining hardware standard.