Will disagree a little with some of the comments.
I have used a Garret pointer for a few years, its a good pinpointer. Whilst you wont be able to scan like you do with a detector and thus cover much/any ground, I took mine to a site where I knew from the glass shards and bits you could pick up that there would be other finds there, but using a full MD was not an option.
So I sat in the baking sun probing carefully, some bits were right on the surface but covered in a thin layer of dust that made them impossible eyes only. Others were an inch or so under the ground, and of course sitting down looking intently meant I spotted bits that I wouldn't have had I been standing up and walking. On those three trips I made some of my best battle field badge & button finds, some of unusual units that I knew had been there.
So in short it can be very useful, but not just in a random area, you need to be in amongst it so to speak