IMO the main value of a personal coach is skills development. I was coached by a local triathlon coach a couple of years ago who was present every bike and swim session (group coaching). He gave me loads of useful technique feedback during those sessions, especially the swimming. The tips he gave me for transitions has also been invaluable. I’m less of a numpty in T1 and T2 than I used to be anyway 
Unfortunately he’s moved to the sunnier climes of Southern France so I’m back to been self-coached.
When it comes to paying a remote coach to send you plans though I really can’t see the value. If they aren’t able to give you feedback on your technique then I think you end up paying a big chunk of money for little benefit. If you spend a bit of time reading up on training I think you’re able to create decent progressive plans yourself. The cycling side of it takes care of itself with TR.
I’ve also never understood the logic of paying a coach so you’re accountable to someone. If an athlete is struggling to get the sessions done to the point where they need to pay someone to be accountable to then I’d say they need to question why they’re doing the sport in the first place.