By default Captions to images and charts are inserted in additional frame, which is different from captions for tables and all kind of captions in Microsoft office and other office suites. It would be more convenient if all cations by default would not create additional frames. There are excellent options for paragraph and character formatting to keep captions in certain positions. It was already discussed some 12-15 years ago and there is excellent workaround, but for unexperienced users, particularly for those used to Microsoft office, it would be much more comfortable to have captions outside frames. Additional frame for caption is also inconvenient if document is exported to doc or docx (like the most of the Writer documents, I guess). Users of Microsoft office don't know that it is great tradition to have those frames and they might become a bit angry during deleting of frames.
I agree to 100%