Different people use their phone or features differently. So no perfect phone for everybody. You just buy what you needed. DEX is a MUST for me.

Replace laptop (with data) when traveling and no worry about it being stolen in hotel.

I have a cheap lightweight touchscreen monitor and with just one cable, can share photos on bigger screen with others.

For monitor, you can either bring along a cable to hook up to hotel's TV that cost ~RM20. With modern TV, you can even hook up wireless.

Or buy a cheap lightweight touchscreen monitor costing less than RM400 running off purely on phone's battery. I have this because sometimes I want to share phone document/photos with others. 14" beats 6+" anytime for  effect 

For mouse or keyboard, you can either use the phone's inbuilt or buy a cheap Bluetooth ones.