Airsoft VS Paintball
A paintball is about 3 grams and travels at about 300 ft/s, carrying about 13 joules of energy. In comparison, a metal bb from a bb gun carries about 18 joules of energy.
An airsoft pellet is 0.2 grams; traveling at the maximum allowed limit for an airsoft gun it delivers only 1.49 joule of energy, so it has much less impact compared to paintball, thus it is much safer.
Airsoft is also much less messy. There is no paint to clean up, and NTA uses biodegradeable pellets, which disappear from view within a week, and fully biodegrade in as little as 10 weeks.