A landmark is an inventory item (making reference to an inventory asset on the server side). It is not "pastable" on the 3D view...
The Cool VL Viewer implements a "Teleport history" floater (the entry to open it is in the World menu; you could also associate it with a Lua side bar button (*), for faster access), which got a "Favorite places" tab, listing all the spots (parcels) you TPed to 10 or more times, with the most frequented spots listed first.
Using Lua, you could also implement your own favorites teleport floater (e.g. by grouping your favorite landmarks in a specific inventory folder and using this folder contents under Lua to present you with a menu).
(*) The
example automation script is doing this with the line: