2X teleconverter just double the focal length, and reduces the amt of light by a couple of stops, minimum focus distance unchanged, can focus at infinity
close up filters dont reduce light significantly, allows you to focus closer, cannot focus at infinity.
take for example 80-200mm + 2x converter, 160-400mm, you are still focussing at min 1.5 metres.
80-200mm with a +2 close up filter, its 80-200mm, but now you are focussing at 0.75 metres.