Exactly why I use HN's.why not use the HN for VN so that they have the better seal and don't leak??

Plus they are way better for heating in winter as the seal is inside the bucket/bottle,
plus plus you can set the bucket/bottle down as they are on sides instead of bottom.
VN's are more available in stores and are easier for very young birds to use.
With the HN's I've had trouble getting any age bird to 'learn' how to use them after using an open waterer. Some pick it up quick, some take days or weeks to 'get it'.
There are pros and cons to both, but the HN's won out here.