Complete examination for tonsil disease without having to pass an endoscope down the nose, which can be a bit uncomfortable. A perfectly good view of the lower throat to exclude lingual tonsil and voice box problems, plus an even better view of the postnasal space to exclude adenoid remnant involvement (see the eustachian tube orifices very clearly).
Plus of course the palatine tonsils and posterior pharyngeal wall, seen at the beginning, note the deep cleft behind the left tonsil, where the scope is inserted with evidence of underlying disease. All done via the mouth so no need to pass the scope down the nose.