I got mine in 2014 because I wanted Shimano road disc brakes, and this was when the only option was Di2, so I went for it rather than wait for the release of a mechanical version, which I think I would have bought were it available at the time.
However, I quickly came to appreciate having Di2 and find it difficult to go back. I do understand the ethos that a bicycle of all things shouldn't require batteries for any of the essential functions, but I also think it is a wee bit puritanical.
I got Di2 when I was recovering from a major orthopedic injury that damaged my self-confidence as much as the bones that had to be surgically repaired. Mis-shifts were actually preventing me from down-shifting when I needed to, and Di2 was the ideal psychological antidote. Most people don't have such an extreme case, but it does suggest that Di2 shifting can enhance the rider's experience and efficiency.
When my (adult) kid got a Di2 bike (Trek Emonda), he had some pretty bad luck with it failing just before racetime. I think it is working fine now, but it does very infrequently introduce a potential complication. Ironically, I helped him buy the bike by paying the cost difference between Di2 and mechanical, justifying it to myself that it would be virtually maintenance-free (as mine has been for 9 years now, including the original battery). His experience was highly atypical, but it might be worth keeping in mind when making the decision.