Birch plywood and baltic birch plywood are completely different animals.
Regular birch plywood is indeed often the cheap stuff.
Baltic birch will be void-free and of a very consistent quality and made from thinner veneers. It's much more stable and high quality product, although you're correct that it probably won't be as pretty on the surfaces.
Too be honest I've never heard of "baltic birch" before so I can't comment on how different it is from the normal birch plywood we get here in EU.
I just googled it and saw that it looks exactly like the birch plywood I have been using, so I assumed that it has similar properties.
I consider birch to be "good" plywood, it's very easy to work with, strong, and seems somewhat resilient to warping. However, because the layers are so thin you often end up breaking bits off when working on it with a router, and the surface somehow doesn't get as smooth when sanding.
The 3-layer boards (not sure what they are called in English) seem to be easier to sand smooth, easier to finish with oil, and are not as finicky when routing.
Just from looking at pictures, I'd assume the bamboo boards are closer to the 3 layer stuff rather than the 13 layer stuff.
Regular birch plywood is indeed often the cheap stuff.
Baltic birch will be void-free and of a very consistent quality and made from thinner veneers. It's much more stable and high quality product, although you're correct that it probably won't be as pretty on the surfaces.