Weird??? I really don't think so- and if parents are making a will- it is really helpful, in the event of a terrible accident or illness, etc- for things to be clear. And to protect children from possible greedy relatives (sadly some families do have them), etc- and to put some moeny for the bringing up of the children and their studies, and put the rest in trust, etc.
It is only as weird as making a will. A large proportion of people die intestate and this causes untold trouble and misery for the family, and huge costs too. A friend of ours would not make a will right into his 60s because he thought it was 'weird' and bad luck. How daft.
Do it, make arrangements, and forget about it - nothing weird about it.