Haru Taikais - What are they used for?

In the Kokoyakyu calendar year, everything seems to lead into the next thing.  The 秋大会 (aki, or fall taikai) leads to 春甲子園 (haru koushien or senbatsu).  Then there's the summer qualifying for 夏甲子園.

But what puzzles me is the 春大会, or haru taikai.  They don't seem lead to anything.  It's not like it's used for qualification to any 甲子園, so what is it really used for?

While I don't have a fully concrete answer right now, I can only fathom several possibilities.

One thing that I can say for sure, though it is not uniform across the prefectures is that that the top finishers get the top seedings for the summer prefectural qualifiers.  This is definitely the case in Okinawa where Okinawa Shougaku, Kounan, Okinawa Suisan and Urasoe Kougyou all received the top 4 seeds in the summer prefecturals after finishing in that order in the haru taikai.
Now, of course being a top seed in an otherwise random draw doesn't necessarily mean a whole lot - perhaps a first round bye (two byes if you're in Aichi - which actually makes a difference).  But compared to other prefectures where they use last year's top 4 (or more), it certainly seems like a better indicator since most schools have a bevy of 3rd years on the roster who have obviously since graduated.

If you're in a prefecture that doesn't use the haru taikais for Natsu Koushien seeding, then the only other thing I can think of is that it gives teams to work together as a team in a simulated tournament setting before the Natsu Koushien qualifying.  During the fall taikais it was the 1st and 2nd years participating (now 2nd and 3rd years).  Now with the incoming freshman class, it gives teams and managers the ability to evaluate talent against competition outside of single game settings.

The drawback is the same as the fall taikai. Since Haru Koushien is an invitational, all one team really needs to do is to get into the field of qualifying teams.  Now, the committee has passed on teams that if we went from top down would qualify.  But if one can make a good case with their performance, generally they are accepted.

So let's say you're in the Kinki super-region where they qualify 6 teams.  Unless you had an easy road and got annihilated in the semifinals, or perhaps skated by a couple of games, chances are if you make the semis you're in.  So outside of the pride of winning it all (which being Japan obviously means something), there is something to be said for giving away too much information to your possible opponents about your team.  Heck, I've even found videos that have had things blurred out so you couldn't see players or the like - until Koushien was over.

So while you may get extra work in, it can also be a place where people get to see your new, or congealing talent, and for people to prepare.

That's all I can really come up with for now.  But since it can at least shed some light on possible teams to track for the summer, I'll be giving the haru taikais (including super-regionals) some coverage of the next couple of weeks (Shikoku and Kyushu have already concluded).