This not a 3/4 bath, it is a full bathroom that has a shower and not a tub. Very common here in S Fl to have bathrooms with just a shower and no tub.
The marketability issue, if any, is that it is a three bedroom with just one bath instead of the more common and in demand 2 baths. A 3 bedroom/one bath is only seen here in older areas or very cheap starter houses so in those cases other market sales would be similar.
The real problem is there is only one bathroom
A single bathroom home is a functional issue? Not in the market I service. Many properties have only one bath.