The Bilbao bizkaia tourist card is temporarily suspended, so it cannot be used.
Even when Bizkaia card is active, I do not recommend buying it.
The must see attraction Guggenheim Museum is only 13 Eu entry while a day card costing 30 Eu will never be able to justify the cost even with free entry to other museums that you will probably not visit on a short trip, and shopping or dining discounts.
When it was active, the Bilbao Bizkaia card was available for a period of 1,2 or 3 days priced at 30, 35, 40 Eu. The card included free entry to museums and monuments including the Guggenheim, unlimited use of all public transport, and discounts at many local establishments.