But I thought the only picks that succeed in the MLB draft are top first rounders?
So signing the 37th overall pick is irrelevant in the scheme of things, no?
Cease was ranked in the top 15 picks prior to hurting his elbow IIRC. As for the point you're getting at, I care less about the position you draft and more about the money that position gives you. The 4th pick is a $4,621,200 slot. Washington finished just outside the playoffs and got the 18th pick worth $2,145,600. Their entire draft slot money is $5,275,700 or roughly ~$800k more than just the #4 pick by itself.
Simply put, there's often not many teams that can even go after prep pitchers with strong college commitments because that's far less money in the second half of the draft. For example, Rodon was said to be asking for $6 mil and the sox have $5,721,500 in slot money for the #3 pick. You can go 5% over without penalties which basically will allow the sox to sign him around $6 mil if they so choose but there's not much if any left over to go after an over slot player later. The 44th pick drops off pretty heavily to $1,282,700. So while you could do an under slot in the second and save some money, even if they saved $400k that's not really getting you that far toward signing a prep player out of a strong commitment. In the case of the Cease, no one was going to give a prep pitcher a top 15 pick when he has an elbow injury. And because of the way slot money works few teams could afford to draft him later and still have enough to convince him out of a college commitment.
The MLB draft has always been some what atypical in that the most "talented" players didn't go in order of talent. It's been teams that had flexibility with money that often were able to score talent later. However the slot system has changed who the teams with "money" are.