Personally I treat it as a golem. It's an illusion, not a "real" creature and as such has little or nor motivation or personality of it's own. While it follows your commands, it will follow them literally. It's not completely unintelligent because that would be annoying, but it doesn't need to eat, sleep or defecate.
It doesn't act on it's own initiative or have any motivation, much less the desire to converse with other individuals or read a book. It can remember simple things, but it's never going to really comprehend any deeper meaning although it could probably parrot what it heard if asked.
Sure.
While that answers the OPs question, it does not even attempt to address the real balance issue imposed by the spell.
That is why I prefer a different approach to the OPs issue.
To me it's both more interesting AND better balance if the Simulacrum is given independent will (much like an Awakened animal).
Not only does this present an interesting role-play challenge - "what would you do if one day you realized you were created, and consisted of magical ice?"
It also gives the DM all the power he or she needs to shut down abuse with "I won't do it".
I definitely consider "let's cast this spell to create a disposable copy of myself that I can use as a pawn in dangerous situations, and/or save a truckload of spell slots" to be abuse here.
I realize that's pretty much what the spell was intended to do, so I can't argue if you simply keep the spell as is.
But in my game that's pretty much the only option if you want to avoid me banning the spell completely. Yes, it's that ill-thought-through and overpowered.
Keeping the spell as-is basically negates every check and restriction on high-level spellcasters that 5E added. (Especially thinking of casting the spell through Wish here.)
If y'all are fine with that, by all means keep it. I'm not.