Why programs nowadays install itself into AppData/Local in Windows?

I'm like 99% sure this is to get around requiring Administrator access to install.

The user has to have at least Modify permissions on their AppData folder in order for basic account functionality to work.

By installing into AppData/Local these applications get around the requirement to have an administrator or UAC prompt authorise the installation.

Google Chrome is a good example of this. If you cancel the UAC prompt, it will realise this and ask if you'd like to install without Administrator access, then it installs into a location, like AppData/Local that the user has the appropriate permissions.