I think Adrien is saying it's unprofessional and unethical based on the fact that clients are forced to use these particular "interior designers" for doing the actual construction work because they don't detail any specs. Therefore, you can't hire a third party to do the build job.

If your firm is a design and build but provides specs and detailed drawings, and doesn't trap you into using its "build" department, then good for you.

The "technical" aspect of the job is missing, if you think about it. What you are saying is that the end justifies the means. And that regardless of the quality of the drawings and specifications, so long as you get an end product that is satisfactory, why should there be an issue? But this leaves the door wide open to poor quality standards and practices in the industry. It's unregulated enough as it is. And since there are so many conmen on the home reno market, detailed work or "substance" as one might call it, would give someone peace of mind.

Furthermore, that value comparison of 3D & furniture layout only vs detailed lighting, m&e, mood boards, furniture, floorplan, etc just shows it all. Why spend an equal amount of money for less, when you can get more? If you can have such attention to detail, to providing a quality service that allows your customer the freedom to make his or her own decisions without adversely affecting your own credibility as a professional, then that is substance.

Really, they are mislabeling themselves as interior designers if they're only doing 3D work and furniture layout. 3D visualiser and interior decorator is more apt. If you design and build this way, then you have to say "build w/ interior decor consultation & 3D rendering available".

I applaud your professional integrity. Not all of us are so easily hooked by pretty renderings though. Although, there is some confusion as to what an interior designer actually does. 3D Visualisation is one thing, actual design co-ordination is another. Even an interior decorator is a different profession.

Continuing the leather bag analogy,

You buy an LV because you know it's going to last. Granted, it's a luxury brand and therefore a status item and branding is part of the reason why it costs a lot. Still, you know you can trust this brand because it cannot afford to tarnish the image and quality of its products. Quality control in a brand such as LV (or any other luxury brand) is held to the highest standard. This is also an investment because you can still re-sell your luxury item as a secondhand designer bag. Some bags even appreciate in value because they are increasingly very rare in numbers (limited edition, exotic skins, unique craftsmanship, etc).

Value is relative to the needs and wants of the client. You want something that will last, and/or you're going for a look that screams "brand new, showroom, etc", you should be willing to pay more for it (of course, how much more also depends on your budget). Don't always necessarily go for the cheapest option. Go for the best value-for-money with proven quality.

"Professional" being the operative word here.