Dickies Men's Classic Bib Overall

Are they actually wide enough to fit over work boots?

Absolutely; the straight-leg cut is specifically designed to be wide enough to accommodate work boots easily, a feature frequently praised by those in manual trades.

Are these comfortable for all-day wear?

Yes, most users find them very comfortable for full-shift wear, citing the soft feel of the material after a few uses and the generous cut that allows for excellent mobility while working.