Teams can be used in various ways.

For Waze partners (TV or radio stations) it is a social engagement feature where Wazers can connect with the stations through their Waze app to share live updates, photos and reports directly with the Waze partner.

It can also be used by Waze during special events, for the soccer world cup people could join country teams to display the flag of the country they supported

Advertizers can also use it to offer limited or exclusive features to Wazers who join the team, like Disney did recently when you could join the Star Wars team, which enabled road goodies on the map that you could eat to earn points (like in pacman) and they had the shape of Star Wars themed objects (light sabers, R2D2, etc...)

These are just a few of the options it is now used for.