Having working in the recording industry, I have some strong feelings on this one.
Fist I want to say that there is plenty of creative stuff that can be accomplished with the aid of technology that cannot be accomplished without it. In this way i think of it as a creative tool and to some degrees it can be viewed as another instrument. Example of this being done well can be found in bands like Radiohead, the Beatles, as well as the Queen song "Bohemian Rhapsody" (this song was made using multi track recording techniques that I would consider "technology". Even though this song could have been recorded with a choir instead they performed a choir worth of voices by overdubbing the four voices over and over again).
In the OP's question he uses shifting the trumpet up an octave artificially and this reminds me of a guitar effect that is used all the time.
But i think at the heart of the matter is the "making myself sound more proficient than I am" and to this piece I say that you have to do what you feel comfortable with. Let it be known that every recording I worked on (and I am talking about major top 40 bands and artists) had some degree of assistance from technology to make them sound more proficient than the recording would have been otherwise. If this meant editing drums to the grid, tuning vocals, recording one note at a time (yes this happened), cutting multiple takes together, editing out breathes, and everything in between I saw it all happen. It is actually one of the reasons I left the recording industry (there were others, but this really bothered me) and I think there are still artists that don't do this (or at least claim to not do it) such as Jack White (formally of the white stripes) but if you feel comfortable editing yourself to sound better than it is fine and actually very common.
My biggest problem with this is not the aspect of cheating though, it is the fact that I feel it removes the elements of human performance that draws me to enjoy a piece of music. I feel it is the slight imperfections that make a player sound like a player, whether it is Ringo's slightly behind the beat feel or McCartney's slightly flat pitch, if you remove those elements you are removing the essence of that player. If however you are using it as a crutch to help you sound as good as you want to sound, perhaps you can use it as a tool to help you improve to the point of actually being able to perform that way. record yourself, edit it to sound the way you like, practice along with that recording and then record yourself again to see the improvement.
If you have a creative idea that needs to use technology to create, then by all means go for it.
just my opinion. just make good music. ;)