It kinda does. With the technology they have right now, I'd take interactive-javascript-capable Opera Mobile over proxying Opera Mini any day. But if in a year, Opera Mobile can make, one way or another†, Facebook or new Twitter or Google-Wave-of-the-day or any modern website noticeably faster, I won't care much if it means my data is going through Opera's servers, just like I don't care my email is on Google's servers.

[†] super-effective image and content compression? Elimination of multiple-server DNS lookups/requests/transfers? Compiling Javascript into a device's or Opera-internal "native" code on the server? I don't believe we've seen the last yet.

"With the technology they have right now, I'd take interactive-javascript-capable Opera Mobile over proxying Opera Mini any day."

Take a look at the Turbo feature in Opera Mobile. It's similar to the Turbo feature on desktop. Once again, data is being sent through the server and it is being compressed. However, Turbo is capable of handling interactive-web-content (JavaScripts) because the rendering part is still being done locally.

To be quite frank, I found that Opera Turbo rarely sped me up noticeably, and sometimes slowed me down. Just one user's experience in North America today, but there's definitely room for improvement.

If your net speed is more than 512 KBPs you are not going to notice any improvements whatsover, rather (as you said) you might notice delays due to the increased overhead. However, on slower connnections the effect is marked. This is because a 100 KBps connection can download 100KB in 1 sec and 200 KB in 2 sec. On the other hand a 10 KBps connection will require 10 sec and 20 sec respectively. And, in this case, the effect of Opera's compression becomes noticeable.

P.S. What Opera is doing is similar to what www.onspeed.com does. I used to use that during my dialup days, and it was a big big help.

Advertising expands as to fill the available computing power. Content may too. There'll always be a place for an optimized browser, even if just to save battery life.

Yes, because Opera Mini can run on faster phones, but most sold phones are still the cheap ones, and that isn't changing any time soon.

And with operators cutting down on data plans, limited bandwidth isn't going away any time soon either.

I doubt it. Not only phones get increasingly powerful, but the core is also evolving, transitioning to IP and LTE being just around the corner; I believe pilot deployments have already started in the US and Japan.

The problem is that most of the world is not going to be using these powerful phones, and in the parts of the world where you can use them, operators are already killing unlimited data plans.

You are living in a dream world if you think compression is going away any time soon.