According to MacTracker, the iPhone 15 has
- an Apple A16 Bionic processor
- 6 GB of RAM
- Geekbench 6 scores of 2510 (single-core), 6131 (multi-core), and 22524 (Metal).
The iPhone 16e has
- an Apple A18 processor
- 8 GB of RAM
- Geekbench 6 scores of 3291 (single-core), 8066 (multi-core), and 24038 (Metal). I.e., the CPU scores are about 31% higher than those for the iPhone 15, and the GPU score is about 6.7% higher.
The iPhone 16e is missing some features such as
- An Ultra-Wide (0.5x) camera
- MagSafe charging – it supports Qi wireless charging, but not magnetic help with alignment
- USB-C (DisplayPort) support (e.g., for making USB-C to HDMI connections to a TV set)
If this matters to you, you might want to consider getting the regular iPhone 16, instead.