The Art Student is cheap, has 2 Sanity (so she can soak at least one Horror before she dies) and she will instantly discover a clue at your location upon arrival. If you're feeling generous you can always consider her an auto-success Investigation action for 2 resources, with a free meatshield included.
But there's two problems really. The first is that Art Student is a Seeker card, and Seekers are quite good at finding clues. They really shouldn't have to pay 2 resources for a severed tentacle when they can find one for free. They also often get benefits from investigating, benefits this card wont trigger. The second problem is that Seekers have far more attractive allies - Dr. Milan Christopher for example.
"But!" I hear you say, "I can play the Art Student first and then discard her when Dr. Milan shows up!". That's fine and dandy, but what if you have already played Dr. Milan when you draw the student? Then she's just a +1 Knowledge skill card, silently mocking you from the safety of your palm.
"Charisma! I can include Charisma in my deck!" you clamour. Well, you certainly can, but as they say in Kathmandu; "you'd be paying the baker for the benefit of a horse". It's simply not worth the trouble.