Why was home encryption dropped in the 18.04 installer?

You can no longer choose to encrypt your home directory with the Ubuntu 18.04 installer. Why?

The official release notes for Ubuntu 18.04 state:

The installer no longer offers the encrypted home option using ecryptfs-utils. It is recommended to use full-disk encryption instead for this release.

Why? Some people claim that computers are now so fast that it doesn't matter. This is simply not true.

• My Android tablet with full encryption is ~40% slower on read and ~15% slower on write actions.
• My Atom laptop with LUKS seems fine with simple tasks, but adds a ~40% CPU overhead in I/O. Why would I want this performance penalty while gaming and the game is streaming levels and textures from storage?

Encrypting the full disk does not seem necessary. The operating system and software packages are publicly available, they are not private.

I'm assuming there are other good and more specific reasons. I'd like to know them.