Antialiasing and other display enhancement techniques.
I doubt that it's development costs. An educated guess is that those apps that do not use such features are doing so to reduce resources being used and to keep up speed. Some apps that I use such as Gerber Omega, Filter Forge, Genetica and others allow you to choose to display lower resolution images in the workspace, lower the sampling amount of the antialiasing or turn off antialiasing altogether.
In Filter Forge, for example, which can be extremely processor intensive, one can turn off anti aliasing to greatly reduce the time it takes to generate a high resolution image. I usually generate images at 3,600 x 3,600 pixels when using Filter Forge software. At that large of a size, antialiasing has pretty much no visible difference in the result and processing time can be reduced by 50% or more. An image that takes 45 minutes to process with antialiasing will take 20 to 22 minutes with it turned off.
From Webopedia.com:
In computer graphics, antialiasing is a software technique for diminishing jaggies - stairstep-like lines that should be smooth. Jaggies occur because the output device, the monitor or printer, doesn't have a high enough resolution to represent a smooth line. Antialiasing reduces the prominence of jaggies by surrounding the stairsteps with intermediate shades of gray (for gray-scaling devices) or color (for color devices). Although this reduces the jagged appearance of the lines, it also makes them fuzzier. Another method for reducing jaggies is called smoothing, in which the printer changes the size and horizontal alignment of dots to make curves smoother.
Antialiasing is sometimes called oversampling.