Transitional Lense, Is it worth it?

I was talking to a friend today and she works in a eye glasses store. I asked her if it's worth to purchase transitional lens for it's flexibilities to turn into sunglasses under UV sunlight. I read some of the marketing material on transitional lens. Generally the marketing gears toward how much it can protect your eyes and the fact that it's 100% UV protection, so on and so forth. Is it really worth getting the transitional lens? I am still not too sure. Another question I posed to her is how does the transitional lens work meaning how long will it take to transition from dark to light? She said about 6 minutes or so. Hmmm....6 minutes is a bit long? Don't you think?

I work for a professional IT support environment. Imagined having you eye glasses transition from light to dark when you need to visit a user. It is really inconvenient to wait 6 minutes for the lens to transition back to clear. I can understand how cool it is to get into your car and "Bam", you got sunglasses. Well, to keep it brief, I got a decent clip that costed about $30 and it's lasted me for a while. Spending over $300 to get some cool lenses and convenient, what a price tag. Don't forget if your eye prescriptions need to change each year which means you have to get another transitional lens. Please feel free to put in your two cents. Love to hear your take on this.