These days, is it still better to buy a computer monitor than a large TV screen?
One problem with using TVs as monitors is that you would be hard pressed to find a native 1440 TV, let alone a native 1600. So first, your only choice is going to be 1080P or 4K. And while a 4K TV will do 1440, it is inferior to a native 1440 panel. We can argue this, but to my vision, it is clearly best to operate at a native resolution.
Using a 4K TV as a monitor has it's own set of problems as you have to make sure that it is capable of 60Hz at 4:4:4 Chroma Subsampling which would require HDMI 2.0. They are out there, but that increases the cost. Using Display Port is much better than HDMI, but few TV's have Display Port. If you are using a TV with a Mac, this is a particularly problematic issue as Apple's implementation of HDMI is limited to 30Hz. You could use an active Display Port to HDMI 2.0 adapter/cable, but again you are adding cost and hassle.
A second point, is that monitors are designed to be used with a computer, while TVs
can be used. For example, if my computer goes to sleep, both a monitor and a TV will eventually shut off. When I wake my computer, the monitor wakes as well, but the TV has to be turned on. There are many other ways that TVs are not tailored to use with a computer.
Having said that, I have used TVs over the years for monitors, both 1080 and 4K. And I was relatively happy, but I finally bought a Dell 4K monitor and the experience is far, far superior to using a TV.