I much prefer minutes played as a reference. I feel that appearances is too vague. Two players can play in 101 games, with one playing twice as many minutes as the other, yet the '101 appearances' doesn't allow for proper comparison.
3,075 minutes (eq. of 34 full matches), 16 goals, 3 assists in the Premier League
1250 minutes (eq. of 13 full matches), 6 goals, 2 assists in Europa
646 minutes (eq. of 7 full matches), 3 goals, 1 assist in FA Cup
212 minutes (eq. of 2 full matches), 1 goal, 2 assists in Champions League
Seen from a minutes per contribution perspective, his performance at 19 is even better than your original observation even, which is phenomenal.