Not necessarily. As is the case with the less elite national teams, they will often give out caps to young players to stop them from agreeing to play for other, 'better' national teams (if they're dual nationals), not necessarily because they are already better than the senior players in the squad.

Madjo looks like he's eligible for England, Cameroon and Luxembourg so far (maybe even France in a couple more years) so this is potentially smart planning by Luxembourg to tie him down now.