One thing that does matter: regardless what they do with your body, it costs money, usually money that comes out of your estate or gets dumped on your children.
Having a pre-designated tomb already paid for alleviates that at least, much less cost on your loved ones and one less thing for them to have to worry about in their time of grief.
It can be kimd of challenging to, right in the middle of grieving, having to stop and handle all the beaurecracy and pricing and etc.
Having that settled ahead of time allows your loved ones to focus on just grieving. And I think thats good.
You might not realize it but I think this alone demonstrates your dad is thinking about you here, he is handling his own funeral proceedings so you wont even need to think about it when the day comes. Thats a very kind thing to do, even if he doesn’t say it.