Redecorating rooms are the biggest cause of people wanting to move radiators. As you can see here, new radiators can make a big impression on how a room looks. I do it alot.
Placing an upright radiator under a window like this is rare. It looks good and luckily it also works.
Unlocking a room’s potential is important. You may want a new settee and there is not enough space. Move the radiator. It usually means a system drain down, and a good chance to give it clean water and extend the life of your system.