I do see your point entirely.....

I think it depends where you are coming from - whether you need to do things professionally, or develop yourself as an artist.

If you're doing something professionally, then a lot of it is down to how much time something would take for the best possible results. Bryce give the landscape you want? Use that. Don't need wonderful looking people for pre-vis work? Use Poser.

However, if you're looking to develop as an artist, and time isn't as important, then I think you should be willing to do the work yourself, but, at the same time, be aware of the areas that you are trying to improve and use 'shortcuts' for the other areas....

If you're trying to improve as a modeller, then you wouldn't want to use Poser or Bryce.
If you're looking to become a Particle TD, then you would work with the standard particles, and work on getting great results from them, rather than using a pre-built particles plugin.
If you're interested in Character Rigging, then you'd create your rigs yourself rather than using a rigging script.
If you're wanting to animate, you'd keyframe your own animations, rather than using mo-cap data.

All of the things I've said you "shouldn't" do are perfectly valid things to use in a professional environment, as long as they give the desired results - but it all depends on where you are coming into it from.