Very narrow minded attitude. Might be unusable for you but great for others. Try to keep the tone a bit more friendly.

I think it depends on your eyesight and programs. I have a 13.3″ laptop, but I just use vim and a pretty small font. My favorite laptop ever was the Toshiba NB305. At 10.3″ it was a "one app full screen at a time" machine, but that was appropriate for the processing power anyway.

In my case I sometimes work from home and sometimes from the office. The laptop is handy since I can bring it with me and use the same computer at both workstations, both of which have external monitors.

Because I am disallowed from accessing company tools and network with my personal devices. This is exceptionally common and has been the policy at every company I ever worked for.