If I had to guess I'd say it probably has something to do with the lack of space. Would a huge replica similar to Sophia's statue in Azyz Lla be pretty awesome? Definitely - but it'd take up a lot of space no matter if it were an outdoor or indoor furnishing. The majority of players just don't have enough room. At least with a miniature pretty much everyone can have access to it - assuming they have at the very least a FC room or an apartment.