Why does chocolate tempering requires reaching temperatures where "bad" crystals can be formed
This YouTube video from America's Test Kitchen doesn't exactly address your question, but I think it hits it on the periphery towards the end.

Summary: Dan (the chef) goes over the traditional way of tempering chocolate (much like the method you link to / describe).  Then, he goes over their shortcut version.  In the shortcut, most of the chocolate is heated until it just melts in the microwave, then the remaining chocolate (having been very finely chopped) is added in (and microwaved in 5 second bursts, if it doesn't melt with the residual heat).  The result is close to, but not exactly the same as the traditional method.

My take-away and guess as to why: In the traditional method, a mix of type IV and V crystals are formed, but, I suspect that there are also some quantity of type III as well (in small pockets that are not the same temperature as the rest of the mixture).  I suspect that the creation of the different types helps keep crystal sizes small - which is one of the desired conditions of tempering.  By allowing the mix of small crystals to form, then melting the undesired ones, you may be allowing more smaller crystals a chance to form, instead of larger one.  If this is true, it might explain why the second method produces a slightly inferior temper: the seed crystals might be too large (from the just recently melted chocolate), and their initial growth is uninhibited by other crystal types.

I've just checked with my BakeWise book (tempering chocolate p 104-107) by Shirley O. Corriher (Amazon link).  On pg 106, she mentions that cooling dark chocolate to 82F/27.8C ...


  allows some undesirable crystals to form, but it gets good
  crystallization of the Form V crystals started.


She also mentions stirring constantly several times over.  This is usually an indication that one is trying to A.) keep temperatures uniform throughout a mixture and/or B.) promote small crystal growth.  (It's why ice cream makers constantly churn, instead of just chucking the mixture into a freezer.)

So, I'm going to stick with: formation of lots of small type V's, even with some type IV's, is more desirable than the formation of fewer type V's, but with no type IV's.