Though, in my opinion, the only touristic attraction to non-believers is... people and the strength of their faith, Fatima is always crowded with tourists.
If you decide to be one more... OK.
You just have to respect the pilgrims, and make the merchants's happiness, but remember, nearby, you have some priorities that would make you feel sad if you miss them to see Fatima:
I'm talking about Batalha, Alcobaça, and Nazaré... and Óbidos... and...
My Austrian friends Ingrid an Johanna wanted to go there, in winter, we did, but (I was in command!) respecting the touristy priorities
Souvenirs, souvenirs, souvenirs
We sell everything! All kinds of crafts from wax to jewelry, statues, toys, clothes, paintings, and all you can imagine, are available around the hotels, hostels, restaurants, stalls, shops that ARE Fatima.
It's easy to find some "Portuguese" crafts made in China, and if you search a little more, there's also Taiwan, Morocco, India, and many more, even... believe me... Portugal.
So... hurry! Go search! And buy! Buy! Buy! For me ... bye.