This is more a long commentary with some thoughts about this than an answer.
I already used that in puzzles that seemed to be too hard or too boring to be manually solved. Frequently I use this as a last resort when everything else fails.
Should we forbid that? Perhaps, but this may simply not work, at least not in every case. If someone post a computer generated solution and says that it is manually generated, how to prove to the contrary?
Further, if people are trying computer generated solutions, this could be a sign that the puzzle is too hard or require too many power from our poor human brains.
And of course, there are some puzzles that can't be really solved without resorting to these or are even designed expecting people to use those.
And again, computer generated solutions are normally inferior to manually generated ones. Why? Because in a manual solution, you can (normally) explain in detail what logic steps you taken to reach the solution, but this is rarely possible in a computer generated one, specially if brute-force (i.e., it just blindly tries all the millions possible combinations until finding the correct one). So if there are two equally valid answers, one computer-generated and the other detailed and manually-generated, it is expected that the manually generated get more upvotes and is more likely to be accepted.
And about the fun, creating the program to find the solution is a valid skill in puzzle-solving. You might say that it is not expected at least in some cases, but it is valid nevertheless. Further, as @A E said in a comment below:
If I can see the algorithm (source code or pseudo-code) then that's often clearer (to me) than a plain-English explanation of the method.
And about this commented by @BmyGuest, also below:
Nothing wrong with first 'cracking' a puzzle and then thinking how one could have arrived there with logic alone...
I totally agree with that.
So what to do? Creating puzzles that needs human brain-power instead of just juggling bits around until it fits is a good start. Except, of course, if you see no problem with that.