HI,
To me, Bitcoin is best for invest in Digital Currency than ethereum. Here the reasons:
* Ethereum is not just a digital currency
* Bitcoin is deflation while Ethereum is inflation
* Bitcoin is simple and limited
* Bitcoin has a first mover advantage
* Bitcoin have bigger community and Its easier to get started
* Ethereum is less known and younger
Hope you get your answer.

You explained it well and simple even a teen can understand what you said. Bitcoin is totally the first virtual/digital currency thats being launched on 2009. While Ethereum is the largest and well-established , decentralized open platform that enables smart contract. Both of them are powered by a distributed ledgers and cryptography. Bitcoin has large community and its ever growing and Ethereum is being second to it.