The property arguments lose quite a bit of weight when one considers that the proposee has the option to still say no- combined with the minuscule odds of the father saying no. If you think the father will say no for whatever reason, reevaluate the relationship or him; then proceed however is fit.
As GDL has said well, it is tradition. If you do not agree, do not do it, if you think you ought to and appropriate do. I feel that if you think he will say yes, then it is appropriate, if you think there is a chance of no, you need to ask why and proceed with care (and maybe some self-reflection). Your GF can be your guide, as if you are close to marriage, I think the conversation easily comes up. Or, if it has not come up organically, you can bring it up pretty easily- "I heard Jim asked Sara's dad first, I thought that was nice...."