Editors like Illustrator can save out some really dumb SVG code sometimes. Properly optimized SVG files can be as much as 80% smaller. Bunches of empty groups, pointless attributes and many other inefficiencies decrease readability and reliability.
Every SVG file should be manually optimized in 3 passes using:
- Your vector graphic editor.
- The SVGO command-line optimization tool.
- Your text editor.