You get 5 free reports on test day. If you don't use them on test day, they disappear and you have to pay for all future reports.

There is absolutely NO reason not to use the 5 freebies while you can.

If you end up applying to a school later on, they'll see all your scores from the last 5 years anyway.

If you end up not applying to a school to which you send a report, that school ignores your score (unless you got a fantastic score, in which case you may hear from them!) - it's not like the Dean of Wharton sifts through the incoming GMAT reports and calls people to mock them for a poor score.