A .22 that easily fits in a G17 or G19 holster?  Yeah, that's a great idea, especially for new shooters learning to draw from a holster and from concealment.  If it has an "actual" Glock trigger, even better to learn on a .22 since all of you pull your Glocks low left!   
 
  If MSRP is $400, maybe we'll see it for $350?  Can't go wrong with that.
10 rounds is a bummer but I can't see it being much more than a trainer and a plinker and learning to change mags isn't bad either.  I used to shoot tons of rim fire learning to call shots and "get my eyes right".  I hated loading up those Buckmark mags after awhile, they would tear my hands up, hopefully these are better?