Software has gotten very good at correcting these three issues, but they still aren’t completely “free” to ignore.

• Distortion: usually corrected very well with lens profiles. This is often the easiest issue to fix in post.
• Chromatic aberration: often reduced very effectively, especially the common types seen toward image edges.
• Light falloff / vignetting: also generally easy to reduce in raw processing.

The tradeoff is that corrections can cost a little image quality. Distortion correction involves stretching parts of the image, which can reduce edge sharpness or effective resolution slightly. Brightening vignetted corners can increase visible noise there. Multiple corrections can add up.

So: these flaws matter less than they used to, and for many everyday photos software can make them much less noticeable or practically irrelevant. But they still matter for demanding work such as architecture, reproduction, or when you want the best possible sharpness and consistency straight from the lens. Software can compensate for some optical flaws; it does not fully replace better optics.