Wide World of Women

I had a 720 HD camera that got better quality videos in indoors places with low light, than a 1080 Full HD camcorder.

The latter gave rainy scenes, while the camera image was smoother and with better contrast, with more clean looking videos.

Is it always better a camera in this situations?

Higher resolution video requires better lighting conditions as the resolution increases. Low-light noise is a royal pita to HD video cams.

Still-Camera's will generally produce better imaging in low-light because the receptor is typically larger and the shutter & apertures can be adjusted for how much & how long light is exposed to the imager. Also add in the fact that most still cameras use flash.

Video in any form will always need better light than still camera's. Most high end HD vidcams have a built in light, but most producers will also set up additional lighting in order to get better results.