Working on a team
Let's face facts... one of the detriments of homeschooling is its lack of group projects (which are admittedly mostly a waste of time, but still teach valuable teamwork skills).  But with debate, you will have the experience of working within a club, depending on your teammates, and on your partner. Excellent preparation for marriage and future jobs. 

 Looks great on college transcripts
Extracurricular activities are hugely important to some schools.  It's not enough to have a 4.23 GPA.  You have to prove you can handle school in addition to other things, crazy, but true.  Debate fills that gap. And winning tournaments is an even more impression notation.

 Taking notes
Another life skill that is less emphasized in homeschooling than public schools is the whole business of taking notes.  It's not always easy to isolate the main idea, write it down in minimal words (legibly), and be prepared to move on to the next sub-point or main idea.  Note taking is truly an acquired skill, and yes, one that can be acquired through debating. 

 Organization
The debater learns quickly that a basic form of organization must be achieved before effective communication can take place.  Therefore, we identify, refute, analyze, and impact even when we dream.  Not only does debate teach verbal organization, but it teaches written organization which is amazingly helpful when writing essays or reports. 

 Research skills
Nothing teaches research better than academic debate.  At the beginning of the season, you'll probably know nothing or next to nothing about the topic. Research skills will also prove useful to you in studying the Bible, current events, or writing essays for class.

 Self-confidence
Did you know the number 1 fear in the world is the fear of public speaking?  Death is number 2.  This effectively means people would rather die than get up and talk in front of a group of their peers.  Debate not only teaches students how to speak in public, but it teaches them how to be good at it.

 Win more arguments
Yes, you too can finally win the occasional argument.  One of the fun things about debate is there is a declared winner-of-the-argument.  After you join debate club, you will find yourself winning arguments in debate rounds as well as winning them outside of debate rounds.  It's fun to be right. 

 Prepares you for life
When people consider future professions for debaters, they tend to think lawyer, politician, journalist, and the like.  But in actuality, debate will help you in any profession that involves talking, writing, or thinking in general.  So unless you aspire to be a cucumber, debate will prepare you for life.

   It's fun
Debate club is fun. We joke around, laugh together, and fellowship with one another. Tournaments are fun.  We encourage one another and in between rounds, practice catching goldfish crackers or spinning in circles.  Some parts of debate are more fun than others, but overall, it's a delicious experience.  I can count on one hand the people I know who tried debate and honestly just didn't enjoy it.  Hundreds of students have tried debate and loved it.  Try it out.  What have you go to lose?