However she got it, Tanaka Rie owning a Dollfie Suigintou figure is one more indication of Rozen Maiden's commercial success in Japan, which I have occasionally posted about on these forums and elsewhere.
For example, see a couple of my lengthy posts on the subject at the Anime News Network Forums: NEWS: Rozen Maiden Confirmed to Restart in Young Jump Mag - Forum - Anime News Network - Rozen Maiden Likely to Gain New Fans with Young Jump;
and NEWS: Funimation CEO Discusses Anime's Future with Variety - Forum - Anime News Network - Rozen Maiden's Success in Japan Not Duplicated in the US.
Rozen Maiden figures, DVDs, CDs, and other merchandise have sold in Japan.
Regardless of origin, few "otaku" anime titles made Character Databank's Top 100 Character Sales Rankings in Japan List for Japanese Fiscal Year 2006:
#27 Suzumiya Haruhi Series (origin: light novel), #74 Mahou Sensei Negima! (origin: manga), #77 D.C. ~Da Capo~ (origin: visual novel game), #91 Rozen Maiden (origin: manga),
#99 Fate Series (origin: visual novel game)...
Pretty good for a very niche title about dolls.