When choosing a hair tool, like a blowdryer or a curling iron, quality will make all the difference.
Clients will say:
“Oh, my consumer blowdryer said it has 1850 watts. It must be great!”

A higher level of wattage only means it’s hotter, but that doesn’t guarantee a better blowdry experience. More horse power in your car doesn’t mean it’s more efficient. It doesn’t means it’s better.

“Oh, my consumer dryer comes with 2 nozzles”
That doesn’t matter. A car that comes with a four season rubber floor mat doesn’t make its performance better.
Professional dryer:
First, the material is better (like a cheaper phone vs iPhone), the wire is usually thicker, its overall design is more durable. You will be satisfied with the investment you make.
Do you think they are the same inside out?
Not just the build of exterior, the motor they use is completely different. Professional dryers use much more expensive types of motor: they are far more durable and produce a much better quality of heat. For example, many dryers, including consumer dryers, label themselves as ceramic, Ionic, infrared dryers. But not all the dryer has same equal amounts of those elements. Some have less than 1% of those elements, which does not add any benefits to your hair. The great quality of a professional grade dryer end up producing much higher quality of heat for your hair.
But what does that do? This keeps more moisture and hydration in your hair and dries your hair faster every time. Long term, it saves you time and, while reducing frizz and giving your hair shine, keeps your hair in much better quality.
Here’s a good description of what I’m talking about (taken from this article):

Quality of construction – As with most purchases (certainly not all) you get what you pay for. Generally a Professional grade hair dryer will be built using higher quality parts and come with more of a guarantee.
Design – Aside from looking like an Italian sports car, a hair dryer’s design will have a great impact on usability and performance. A pedigree, salon tested model will have the benefit of testing in a high use environment. Hopefully the manufacturer would listen to feedback and improve their design over multiple versions. It is surprising how much difference making the power cable two feet longer could affect the ease of use.
Materials – Once again, higher grade equals better materials. If your hairdryer has low quality motor parts or the plastic casing is not greatly heat resistant the decline in performance will be reduced over time.
Power + heat = speed – In a salon environment time is money and the investment of hair dryer that reduces your blow drying time by five minutes would pay for its self in a very short time. If you want great results in a shorter time Then perhaps a Professional Hair Dryer is for you.

Durability – Lastly, A professional hair dryer will blow dry hundreds of heads thousands of times in its lifetime. This means that it needs to be built to a high standard. As a personal use unit it could well out last many cheaper but short-lived models.