The batteries in these are known to expand. Have they been replaced and/or will Google fix them under warranty if they pop open again?
The sale only listed the Woot 90 day warranty, so I would expect that these will not be eligible for Google coverage.
It might spoil the price for you, but you could use the phone until you encounter a problem, and then do your own replacement (ifixit guide here, with a kit that comes to $50)… Or there are shops that would likely do that for you.
Hope that helps.
I can’t remember if it was these models but I’m pretty sure I replaced at least one and maybe both batteries on my two 6 phones before I knew it was covered.
I don’t really think I want to take any chances the more I think about since it would be for my ten year old.