Steam Park: Should danari count be secret from other players?
It looks like you have it correct.
The designer demonstrates hiding his income when explaining the prototype of the game in 2012. (T=8:23 of this video)
He says explicitly in this video from Spiel 2013: &quot;Money are kept secret.&quot; (T=9:48)
Later video reviews and/or game play explainer videos also concur:

Tom Vasel (T=7:40)
Dice Tower (T=10:02)