I think the simple answer to the question is that it's quite important.
When I started to learn about wine and all that it entails, it wasn't long before I started to read and think about glassware. The world of wine is quite complex enough without adding to the complexity, but thats part of the fun.
I have vivid memories from home, as well as my days in the hospitality trade, of the trusty Paris Goblet. Very much a one size fits all glass that is now rarely seen. Most bars and restaurants now have at least two styles of glass. One for white wine and one for red wine. The red wine glass usually being bigger to allow more air into the glass to help enhance the flavour of the wine. Just into the 2nd paragraph and I've mentioned "enhance the flavour".
This is what good glassware is all about. Its not a new thing. Claus Riedel discovered in the 1950's that the shape and size of the glass affected the way wines tasted and his company has continued to develop and improve upon this ever since.
I started with the Riedel Vinum Bordeaux glass for two reasons, the first being I drank predominantly vintage wines of Bordeaux back then and the price was the entry level. I still use them today, although I now have nine different varietal types. Chardonnay, Pinot Noir and so on. A prize to the first person to get nine right in the comments!
These glasses are designed to enhance, (there's that word again!) the characteristics of the specific grape variety and I do find that it really shows when you compare them.
More recently I have upgraded to Riedel WineWings collection. Seven different varietals, but also stylistically very attractive. I love swirling and sipping a vintage wine in these, especially if the wine was a gift and shared with others.
Whilst I am definitely a fan of Riedel there are lots on the market. Some by well known wino's like Jancis Robinson and some by other great firms like Zalto. All carry a similar price, the fun is finding the ones you prefer.