Short answer: No, it doesn't. You can still add yourself as a player.

When you register as a player it means that 
  • you log in using your FIBA 3x3 profile
  • you are added as the first player of the team
  • then you can add more players

When you register as a team lead, you 
  • do not need to have a FIBA 3x3 profile (but you do need to verify your the email address you leave as a team contact)
  • you are not added to the team as a player
  • then you can add more players

The latter option is obviously more suitable for parents of youth players, coaches, manager or agents doing the registration on a behalf of the team. They can easily add players and be the contact of the team but they do not need to create a permanent FIBA 3x3 profile for playing.

Of course, you can first register as a team lead and then manually add yourself as the first player. Then you end up to the same situation as if you had registered as a player directly. In other words, using 'Register as a Team Lead' does not prevent you also from playing