1) Realtors have knowledge beyond the data. Why would you want someone with extensive experience dedicating their time and weekends to resolve your issues?
2) Most likely your home is one of your largest assets. Why would you want the support/consultation of a realtor who has sold/purchased hundreds of homes?
3) If you are buying a home, you do not pay a realtor. Some people are unaware of this. Why would you want a realtor negotiating on your behalf/protecting hundreds of thousands of your dollars/one of your largest assets?
4) Realtors have overwhelming selling/purchasing experience. Who would want that when selling/buying a home?
5) Realtors know the qualified contractors who will get the job done. Don't you want to spend your evenings and weekends tracking down a qualified contractor?