Can you skate indoors, with outdoor roller skates?

The difference is the wheels.

Outdoor skates have softer wheels which makes you roll smoother on streets and sidewalks. They also absorb more shock when rolling over debris. The wheels are bigger.

Indoor skates have harder wheels. They roll smoother on smooth surfaces. The wheels are smaller.

I have 2 sets of wheels and just change them out.

Sometimes little bits of grit get embedded in outdoor skate wheels. Those bits of grit can really scratch up a wood or linoleum floor. That would be my reason for having separate outdoor wheels or skates.

yes. i believe the outdoor wheels have harder rubber than the indoor ones so it might be a tad more slippery on a smooth floor surface.