ETH is much less secure than BTC. ETH has a larger attack surface and has less hash power behind it. If it can manage to fulfill it's vision and is able to innovate through sharding and scalable blockchains, then ETH does have a interesting value proposition, but those things haven't been proven to work yet. Also ETH's use cases require significantly higher data throughput which clogged the network in late 2017 with only a few dapps running. A lot more "ifs".