What an SVG file actually is
SVG is not a grid of pixels at all: it is an XML document describing shapes, paths and text, which the renderer draws at whatever size it is asked for. That is why a 4 KB logo stays perfectly sharp on a billboard, and why the file is often smaller than a thumbnail of itself.
SVGs come out of Illustrator, Figma, Inkscape and icon libraries. Logos, icons, charts and diagrams are the natural cases — anything built from shapes rather than captured from a camera.
What you get from PNG
PNG output is lossless, so the saved pixels are exactly the pixels that went in and re-saving costs nothing in quality. It keeps a full 8-bit alpha channel, which means soft shadows and anti-aliased edges survive against any background.
Universal since the early 2000s, and the format every design tool, browser and operating system handles without argument. It is also the safest format to hand to a printer or a colleague when you do not know their software.
What changes when you convert SVG to PNG
Both formats are lossless, so nothing is thrown away in either direction — this is a container change rather than a quality decision. What differs is how efficiently each one packs the same pixels, and how widely each is supported by the software you need to open it in.
Transparency survives intact. Both SVG and PNG carry a full 8-bit alpha channel, so cut-outs, drop shadows and anti-aliased edges convert without a white box appearing behind them, and the result still composites cleanly onto any background colour.
The important loss here is scalability rather than quality. An SVG is drawn fresh at whatever size it is asked for; the moment it becomes a PNG it is a fixed grid of pixels, and enlarging it later softens the edges. Rasterize at the largest size you will realistically need, and keep the original SVG — it remains the master copy.