Yes. By convention based on old reasons though. When computer screens became common they were low resolution, and a whole genre of serif fonts were made to look good on screens and low-end printers. Good fonts, but adapted to look good in pixel grids. Microsoft made Georgia, Adobe had Utopia to serve the same need. A font like Centaur would just not survive on a screen. Sans serifs worked better, especially the ones with straight lines, Helvetica is easier than Optima on a screen. But now… phone screens and regular screens are good enough to display serifs, but now we are used to sans serifs online. But there’s no real reason for them anymore.
Part of the reason might be that a serif font for something viewed on screen is in most cases (this one included) just out of place.
Yes. By convention based on old reasons though. When computer screens became common they were low resolution, and a whole genre of serif fonts were made to look good on screens and low-end printers. Good fonts, but adapted to look good in pixel grids. Microsoft made Georgia, Adobe had Utopia to serve the same need. A font like Centaur would just not survive on a screen. Sans serifs worked better, especially the ones with straight lines, Helvetica is easier than Optima on a screen. But now… phone screens and regular screens are good enough to display serifs, but now we are used to sans serifs online. But there’s no real reason for them anymore.