Hugo Barra, currently Xiamoi’s vice president of international and formerly VP of Google’s Android vision, on SD cards in an interview with Engadget:
“For high performance devices, we are fundamentally against an SD card slot.”
Barra backed up his statement by pointing out that his team didn’t want to sacrifice battery capacity, ergonomics, appearance and, in the case of the new Mi 4i, the second Micro SIM slot for the sake of letting users add a storage card. More importantly, microSD cards “are incredibly prone to failure and malfunctioning of various different sorts,” and the fact that there are a lot of fake cards out there – and we’ve seen it ourselves – doesn’t help, either.
In case you disagree with him, The Verge’s review of the LG G4 states it’s a pretty decent phone.