Do I need permission from my wife to watch my granddaughter for an hour?

As many of you know my daughter gave birth to my first biological granddaughter about 3 weeks ago.  Mom and baby have gone home after her c-section so it's now just me and the wife here.  As you know, we're both working from home right now.  Today my daughter text me asking if I could watch the baby for about an hour so her and her roommate could go a mile down the road to the nail salon and get their nails done.  She doesn't want the baby in there with all the fumes and things.  I told her sure.  I also told her I go to lunch at 1.  She said she'd feed and change her prior to them arriving and that she'll probably sleep the entire time.  Typical newborn stuff.  When I told my wife that the baby would be coming over for about an hour this was her response.  

"I know you like to jump and say yes to everything your daughter asks so she can do this and that but how long do you think she'll be gone.  It can't be all afternoon because we gotta work.  I assume your lunch break is at 1 but how will this work once you/we are back  at work and she starts crying or needs a diaper change?"

Last I checked "we" aren't keeping her, I am.  She's 3 weeks old not 3 years old running around getting into things.  Now my wife's sons, my step-sons, can come multiple times during the day interrupting her and it's not an issue.  But when my daughter comes by then she's now all of a sudden worried about "our" jobs.  

Do I really need her permission to watch my granddaughter for an hour?