If you'd install ES via deb or rpm or whatever packages from your Distro, this will affect you, as they will be sooner than later removed.

If there's a policy for open source-only usage, you will definitely be affected.

If there will be a diminished number of contributors (which won't like to contribute if it is not open source) and ecosystem (that will stop developing/growing being a proprietary project), you will be affected too.

And you're not AWS in either them.

I'm not sure that if I use ES in my datacenter I would be effected as long as it's internal tool for analysing data.

I'm not lawyer but this is what I understand from their statement.