Why? My Dominican sister-in-laws all work full time, which I assume your wife does not. When I worked full time in the US, I had a cleaning service come in once a week too. For what I paid once a week, I could have someone full time in DR.
When we're in our Dominican home, we have a housekeeper who lives nearby. We pay her what the in-laws pay theirs in SD, which it a lot more than is normal in the campo, and still the bargain of the year. We're only two people unless we get company.
She shows up about 8 a.m., by which time we've already had our coffee. Sometimes she makes breakfast, sometimes I do. She washes the dishes and pots. Then she washes all the floors in the house, adding bleach to the water in addition to the cleaner, to "keep mice and bugs away", then rinses all the floors. Makes the bed, dusts, etc. We discuss what our luncheon meal will be, and she starts cooking the beans. The bathroom is cleaned and sanitized every day. She makes and serves lunch to us and to whoever else shows up [neighbor, caretaker, etc.]. I like to cook, so sometimes I make the main meal. After eating she cleans up the kitchen thoroughly, and insists she has to rewash the floors "because there might be some oil splatter on the floors that will attract bugs/mice". Takes all the trash out to be burned [no trash pick up in the campo]. She sweeps outside several times a day. Changes the sheets frequently.
I'm fussy about our laundry, so I do it myself, and hang it out myself, because she can't seem to get the hang of a typical American double pulley clothesline. She takes it in, folds, irons, puts away everything.
By five her granddaughter is coming home from school, and she walks home, with food for the girl to eat that she saved from lunch. She always offers to come back, and I usually tell her it's not necessary, but sometimes she pops back over - drawn, I think by the sandwiches we usually have at night, she loves the ham, turkey and cheese
Do I "need" her? Not really, but it sure is nice. Last year I was recovering from some emergency abdominal surgery, with instructions from the surgeon "not to pick up anything heavier than my shoes for two months", and so she did absolutely everything for me.