LPDDR RAM is actually a cut down version of DD4, so the differences were already discussed in the above question. LPDDR3 RAM can run at data rates up to 800 megabytes per second whereas DD4 maximum data rate will be an order of magnitude faster. As such, the latency for LPDDR3 (14 nanoseconds) is considerably higher than for DDR4 (9 nanoseconds).
All told, it has less capacity and lower bandwidth performance than DDR4 but is much cheaper. These properties make it more well-suited to running at a low clock speed with very aggressive power saving features. The lower frequencies also help reduce any reliability issues that might arise from use in high-performance devices.
The primary tradeoff is that LPDDR3 can’t handle as much data at once and takes longer to do it.