There are a lot of good Android apps that would be useful on a laptop. There are a lot of Linux apps that are useful on a laptop.
Good security. With secure verified boot. Yet Linux apps that run in a strong sandbox allowing untrusted code. Android apps run in a different sandbox. All this is transparent to the user who sees a desktop.
The Chrome OS and Android are self updating. I don't know about Linux apps yet.
Even Windows can run Linux apps these days. It still doesn't seem to me that that qualifies as "year of the Linux Desktop" as it is intended.
Android is indeed quite different.
Chrome OS is somewhat different. Today I use Crouton to run one or more Linux desktops (currently Ubuntu Unity and Xfce) on my Pixelbook. I've blown away an older Ubuntu 16.04 I had. Thinking about blowing away the Ubuntu Unity and keeping only the Xfce. Each Linux desktop takes about 5 GB with a few additional apps installed including LibreOffice, GIMP, Inksacpe, wxMaxima and Eclipse / Java. Using Crouton means my Pixelbook is in "developer mode" (which means rooted).
I look forward to the integrated Linux apps and expect one day I will switch out of developer (rooted) mode back to normal. This is called a "power wash" on the Settings and resets everything for security and verified boot so no unauthorized code can ever execute.