Visbiome (studied under the name VSL #3) really did reduce the frequency of pouchitis in the research subjects. As Raj points out, though, it’s expensive in the doses that were shown to have benefit. Your surgeon’s approach is much less expensive, and it might well do some good (though you’ll never know for sure). Some people never get pouchitis, or get it so rarely that a daily preventive treatment seems excessive. So an alternate approach is to delay probiotics until you have some evidence (i.e. a case of pouchitis) that preventive treatments have the potential for real benefit. One caveat is that pouchitis can creep up on you, lowering quality of life for months or years before it’s recognized.
If I had it to do over again (with the ability to predict the future) I’d do what your surgeon is suggesting.