The user will click on a second tab if the user is interested in the marker. If the second tab of information is not good enough to the user, then the user will click on a different marker.
The tabs will be activated in the backend: if you wanna use them, then you have the option to use it, if you don't wanna use them, then don't. None will be affected at all, but hotspots having multiple options, it will reach more people .
Clicking on 'read more' you jump to another page losing the actual map with all the information on the screen by the moment. If the user doesn't like the 2nd info is getting, the user will have to go back to the original map, making a lot of clicks in the way back.
With more tabs, the user will get more information in a fast way.