Plasma’s screenshot application, spectacle, has recently implemented OCR (to extract text from screenshot images), so tesseract is a required dependency.
You should install the tesseract-data package that matches your language (for example, for English, install tesseract-data-eng).
The tesseract & tesseract-data-eng packages don’t take up much storage space:
❯ pamac info tesseract | grep Size
Installed Size : 4.8 MB
❯ pamac info tesseract-data-eng | grep Size
Installed Size : 23.5 MB