I've smoked butane hash on a few occasions. Lots of people in california make it where I live, It's a great use of the trim/leaf byproduct from growing.
While it is made with butane, the entire process (and what makes it a very dangerous process) is that you cook (evaporate) all the butane out of the mixture usually with an electric stove type burner.
There is virtually no butane left in the finished product, You inhale more butane from using a bic lighter smoking normal buds than what is in the final product.
As far as the high goes, It gets you really really high and the head rush (instant effects) are much more dramatic. I honestly prefer traditional afghan type hash, where they filter trichromes with a sieve and use a heat press to compress it, its not as pure thc but, imho, it carries on subtle flavors, tastes better, and it's not as intense.
If you don't smoke very often, I really wouldn't recommend it. You will get so high. :3
As far as the chemical argument goes, It's actually healthier than smoking buds. You aren't breathing in as much burning plant material, there is much less for your lungs to process.
And it most definitely is a psychotropic drug in any form (buds or hash). Just like sugar, tea, and coffee but more enjoyable