I think that kicking for touch from that angle would have been a challenge.
Either, play it safe and get between the 10 and 22 - but then have a lot of work to do to score.  As the clock was in the red, this would probably have been a bad call.
Or, aim between the 22 and the 5.  A more difficult kick. Possibility of messing it up. Also, quite a bit of work to do to score.
Or, aim at the 5. Big risk of messing up. Better than average chance of getting a score of some kind providing that the line out goes to plan.
But, Wasps could infringe at the lineouts with impunity as the penalty would have been difficult due to angle.

On the other hand.
- James is a strong kicker. IMO a far better kicker than Smith
- Due to the distance, the angle was okay
- I think there was little wind
- Sometimes, football pitches are smaller that rugby pitches - so, kicking from the half way line is not as bad as kicking from half way at the Stoop.

I think he did a good job - shame it just didn't work.
But, the kick would have not been needed if Boyce hadn't been quite so rubbish when he came on and given away 10 yards and then a kickable penalty.