But here's the thing, you've associated conversation with awkwardness and banality. Neither of those are intrinsic qualities of conversation, it's quite possible to have just the opposite, if you want to and know how to. The key is being comfortable in your own skin, and that's a great quality to have, both for yourself and for others, and both for those with introverted tendencies and extroverted tendencies.
If small talk annoys you (and I totally understand why it does), consider its function. It's meant to be an ice breaker, not the focus of an entire conversation (unless there's no time for anything else).
But the whole point is that it's quite likely that I don't want that conversation. As you say "it's possible .. if you want to". Usually I'd prefer to just continue thinking whatever I was thinking before someone initiated that conversation, the interruption was unwelcome, and I'd be glad if it hadn't happened - i.e., if (s)he had looked at me and decided for whatever reason (such as a phone) that I don't want to be talked to right now.
Being capable and comfortable in such conversations is very, very useful in life (correlates with all kinds of life 'success' measures), and it can be acquired, and acquiring it requires a lot of such practice. However, even with all that, the preference doesn't change - if you are an introvert, you then can do it very well, but you'd still rather prefer not to do it.
For smalltalk - it's likely that I don't want to break that ice; I don't want more friends - I don't have enough free weekends/evenings to spend with my existing great friends, as we've all grown more busy, gotten families and moved miles apart; starting new relationships would decrease quality of existing ones. I don't want to meet hot girls - I'm happily married. I don't want to get to know a random person - if we meet on business, I'd rather keep that a purely professional relationship. If I'm in a mood to meet people and new experiences, say, while traveling - then great; but if I've spent all my "communications batteries" already today - then unless we're very close, I'd rather not have any unneccessary meaningful communications.
I agree conversational skills are 'useful' (if you wish to frame them in terms of functionality), and agree that ability to converse doesn't necessarily alter preference for introversion/extroversion. I disagree that being able to hold a good conversation requires a lot of practice, again I would say it's down to being comfortable in your own skin, but an option for getting that comfortable can be through talking with others.
Speaking personally, throughout my life I've had times when I've been extroverted and times when I've been introverted, and I think both are great. Introverts get to enjoy a rich inner life, and extroverts get to enjoy a vibrant outer life, there's something to be said for both, but best of all is not being restricted from experiencing either (easier said than done).
Just to further our discussion, I'm curious to know what you think about the difference between online and offline conversation, for introverts especially. Does one feel easier than the other, and if so, why do you think that is?
If small talk annoys you (and I totally understand why it does), consider its function. It's meant to be an ice breaker, not the focus of an entire conversation (unless there's no time for anything else).