Most of the price difference is features. A higher end board might have some fancy headers for specific applications, or extra I/O and ports, thunderbolt, or USB 3.1, or Type C etc...
Also, higher end boards will have better VRM setups. A better VRM may lead to a more stable overclock, or allow the VRM not to get as hot. If you're not pushing a high overclock, this probably won't make a big difference. A mid-range board with heatsinks on the VRM is typically a good bet. Something like the ASRock Z370 Extreme4, for example.
Then, some of it is marketing. The Z370-E isn't really any better than the Extreme4, but usually about $40 more expensive because "RoG"
Also, higher end boards will have better VRM setups. A better VRM may lead to a more stable overclock, or allow the VRM not to get as hot. If you're not pushing a high overclock, this probably won't make a big difference. A mid-range board with heatsinks on the VRM is typically a good bet. Something like the ASRock Z370 Extreme4, for example.
Then, some of it is marketing. The Z370-E isn't really any better than the Extreme4, but usually about $40 more expensive because "RoG"