It's visitor friendly, no problem :)
I have just stayed here a week and liked it, funny enough I also stayed here several years ago and not much is changed.
Many Japanese expats stay here long time, so it's pretty quiet. If possible get a room in tower 2 so you don't need to pass the reception all the time. You will pass the security guards though, but no problem.
The premium rooms are in tower 2.
https://www.legacybangkok.com/en/rooms.php
Generally a very solid 4 star hotel. Decent location, big well maintained rooms and nice polite staff. Breakfast is ok but a little boring after a week.
I will stay here again.