I haven’t used GB Studio very much, but I don’t think it has a way to import the hexadecimal format that this outputs.
I could theoretically implement a way to export to JPEG, but if you want a JPEG it’s probably easier to use just about any other fully featured image editing tool.
I could see some use for backgrounds, but Tiled works well and is still maintained.
This is really just intended to support GBDK because the only tool recommended for generating the kind of byte code you need for GBDK sprites hasn’t been updated for literal decades.