Why are children's seats or booster seats best installed in the rear-facing seats?

• If the airbag inflates, it could seriously injure the child.
  Explanation:

  "A rear-facing child car seat is always best installed in the back seat. Never put a rear-facing child car seat in a seating position with an active airbag. If the airbag inflates, it could seriously injure the child."
• Children might distract the driver.
• There isn’t enough space in the front seats for a booster seat.
• There is no specific reason.