Can you be certain that at 3:46 in the morning that you'll be able to pull this up on your phone from bed and it will just work? What about if you are out and left the kid with a babysitter - can you reliably access from outside?
I went through quite a few Amazon cheapo RRSP cameras and they would invariably just stop working randomly in the most scary way for a baby monitor: they'd freeze frame and there is no way to know if the baby is just still or if the feed has hung. I thought about perhaps rigging up some infrared flashing LED or something but this was all a lot of effort and time and energy that as a new parent I just didn't have.
In the end I got some Nest cameras and have had zero downtime and they just work at home and when out and about. Say what you want about Google but I probably trust them more than most places to not let the cameras get hacked trivially.