For example, Kaspersky make a handy rescue disk that you can burn to CD or install on a USB drive for performing offline scans of computers. If these Lenovo computers have crippled access to their SSD drives (intentionally or otherwise) then these tools won't be able to see the SSD and disinfect the computer.
You also have tools like GPARTED for repartitioning disks, DBAN for erasing disks prior to disposal, and I suspect there are a range of other useful rescue and recovery tools that rely on Linux as well.
By not allowing people to use these tools, it's likely that problems that could otherwise be fixed will only be repairable by doing full system erases and rebuilds, or returning the laptop to Lenovo for repair.
The fact that these computers don't run Linux on a 24x7 basis isn't the issue - its that when you need to boot them of Linux (installer, libe install, or revovery tools) the ability is not there.
I doubt it's a deliberate decision by Lenovo - however it does indicate that whatever design and manufacturing criteria they have for their products is not particularly well thought out, and doesn't speak well for the quality and utility of their other products.