Yes you can definitely use a gravel bike on normal road surfaces and many people are finding that gravel bikes actually do a better job of all round street riding than a dedicated road bike.
Gravel Bike Frame Geometry
The more upright riding position due to the frame geometry and less low-slung handlebars helps give you better visibility of what’s going on around you. That means as well as recreational riding, a gravel bike could make a great commuting bike for work too.
Gravel Bike Tyres
Another feature of gravel bike frames is that they have lots of tyre clearance, which lets you run significantly wider, grippier tyres that handle lumpy, potholed streets with ease, and make riding off the road onto gravel shoulders safer. You’llprobably alsofind you spend less time fixing punctures and replacing cracked rims too.
Your exact tyre choice comes down to where you’ll be doing most of your riding. If you’ll mainly be on the road and smooth gravel trails you can go with narrower tyres with a light diamond tread for less rolling resistance. If you plan on going onto rougher, more technical terrain you can spec wider tyres with aggressive tread with side lugs for extra traction.