MMA striking is not Olympic boxing. The goal is not to land as many strikes as possible, but to do as much damage as possible to make progress towards a finish. Watch the replay between rounds 1 and 2. None of the Reyes highlight strikes did any damage; they were a combination of slaps, grazes, near misses, and a soft counter that caught Jones off balance and had no follow-up. Reyes had exactly one damaging strike during the round, a left leg body shot that landed hard just below Jones' guard. Jones had 3 or 4 similarly damaging strikes in the round. Reyes was mostly gassing himself with high volume. Same goes for round 2. Reyes did much better in round 3, doing some real damage and clearly taking the round.
As for the last two rounds, Reyes had a good flurry at the start of round 4, then, for the rest of the fight, he was gassed and fighting in survival mode, just trying not to get finished. Reyes didn't really contest round 4 or 5 at all.
Reyes rope-a-doped himself in rounds 1 and 2, took round 3, and survived rounds 4 and 5 with 9 minutes and 30 seconds of no offense to finish the fight.
I used to think that was a close fight, but my MMA knowledge has gotten much better over the years and, looking back at it now, this was not close. 49-46 Jones.