You asked

What is the sony e 70 350mm f 4 5 6 3 g oss good for?

Here is what the site says about that.

From Sony E 70-350mm f/4.5-6.3 G OSS: Sony E 70-350mm f/4.5-6.3 G OSS: A zoom lens by Sony for APS-C cameras, 70-350mm f/4.5-6.3. Specs - Maker: Sony - Focal length: 70-350mm (zoom) - Maximum aperture: f/4.5-6.3 (it gets darker as you zoom in) - Made for: APS-C sensors - Mounts: Sony E - Stabilised: yes - Autofocus: yes What it frames like - On APS-C (Sony E): like 105-525mm on full frame; f/4.5-6.3 gives about the depth of field of f/6.8-9.4 there. - ...

From Landscape: Lenses: - A wide zoom, around 16-35mm on full frame or 10-24mm on APS-C, is the classic landscape lens: big skies, strong foregrounds. - A standard zoom, 24-70mm or similar, covers most scenes. - A telephoto zoom, 70-200mm or longer, is underrated: it picks out layers of hills, a lone tree, or light on a distant ridge. You don't need fast apertures for landscapes, since you'll usually shoot between f/8 and ...

Quoted from this site's pages.

From these pages