Is it good that donors are anonymous?

Definitely yes. This is evidenced by experience in countries where the anonymity of donors was abolished. These countries (e.g. the United Kingdom) are facing a shortage of egg and sperm donors. Because the donation of eggs and sperm is mutually anonymous, i.e., the recipients are also anonymous to the donor, a situation cannot arise in which the biological mother or father, i.e., the egg or sperm donor, makes a later claim on your future child. According to the current laws of the Czech Republic, a child conceived from a donated egg or sperm has no right to learn the identity of their biological parent or parents, even after reaching the age of 18.