I might tend to agree more with the perspective of  proark (who more recently has seemed like conark  :-). 

 Even though teams can't get physicals before the draft I think they can survey the prospective draftees to get a feel for signability and money considerations, and if they think they can create a 2 for 1 type of situation I think that might be more important than putting all their eggs in one basket.   Typically there are probably half a dozen or so players who might be considered of worthy of the top pick, and while I don't think the Astros would go so far as to bypass that pool altogether,  I do suspect they'd draft as much for 'the deal' within that group as for the individual.