Higher resolution = more screen "real estate" (I hate that term, but you know what I mean?). So, you can work easier on two windows side by side. You could have say a web browser and a spreadsheet running side by side using Windows "snap" feature, and have a better chance of using them both.
I don't know what you currently have, but if it's a good few years old then the fluorescent backlight might well be wearing out, resulting in less vibrant images. IPS screens which were once extremely expensive are now quite affordable, and these give true 24 bit colour without dithering, plus wider viewing angles (no annoying colour shift as you look at it from an off centre position). LED backlights which are now common last longer and use less power.
This Dell looks good value. I haven't owned that screen specifically but I've found other Dell screens to be pretty good quality. LG also make a few good value screens of a similar spec.