Weird - I can almost understand if he thought he wouldn’t use it but she would, that would make sense. But as he’s thinking he’ll buy another one for himself, he clearly just can’t say no to his DD. She said she wanted it and he gave it to her.
FWIW I had similar with my DP once. I made him a gift, took hours, it was quite stylish and based on something he loved - I know he was pleased with it.
He video called me to show me where he’d put it. In his DD’s room, in amongst the Disney stuff and photos of her mum and dad 
.
When I told him I was hurt that I’d put a lot of time and love into making it for him and that he’d just given it away his reply was “it’s not like I won’t see it, I go into her room all the time! She said she liked it, so I gave it to her”.
Reminded me of Last Christmas - “I gave you my heart, the very next day you gave it away”.
DP definitely can’t say no to his DDs and it’s been a long running theme throughout our relationship. This was the first time I really felt the ‘hierarchy’ of his daughters’ feelings coming first above mine.
If this is part of a pattern, beware, it won’t get any better.