It really makes no sense why they pussyfied her material either. One, they already had her kill someone in the show. Two, it would have made way better tv to see her have to endure the trauma at Harrenhal. Now instead they humanized Tywin (why!? I liked those scenes between them, but again, this was in exchange for something that would have been even better, that is to say... the trials and tribulations Arya had to face), and Arya was sitting there in the comparable lap of luxury and of course waited too long to kill Tywin, which again made no sense. Just no sense to be had with the changes the showrunners make. If it's in the name of better tv, I'm all for it - I don't need a literal adaptation - but virtually every change makes the plot nonsensical, and makes the tv show worse.
It's not that they would 'bother' - it's that if they were in the show at all, they would have been there. No way they could have hid giants in that encampment, let alone mammoths. They're simply not in the show, period. Budget.