Are data that do not support a hypothesis useful?

Yes, data that does not support a hypothesis is useful.

Explanation:

As you may already know, a hypothesis is an assumption about something, about some phenomenon, or about a situation. This assumption must be credited or discredited through experiments that will generate data that may support the hypothesis or not support the hypothesis.

In all cases, the data is useful. Data that support the hypothesis prove that the hypothesis is true and can stop being a speculation, to be a truth. On the other hand, data that do not support the hypothesis are useful because they take away the credibility of the speculation, showing that it cannot be carried forward, since it is not true.

Yes. Because the hypothesis is just a proposed explanation pending further investigation. So new data could prove hypothesis wrong.