I think that many entrepreneurs get stuck in this mindset: they've got to look big before they are. The "fake it til they make it" approach. And I get it, though things are changing now, and the artisan is now celebrated as much as the corporation, so needing to appear big is not a requirement any longer.
That's not to say you should just set up an Etsy shop and be done with it, though. Chances are, your business will expand over the years and begin to pull in more attention (and have more needs). As your brand expands, so too should your capabilities to handle customer service, and I think that's when stuff like chat software moves from "bells and whistles" to "required." But how do you know when you've reached that level? Answer these questions:
Can you dedicate time to running it?
The hardest part of adding things that require your time...is that they require your time. If you can't sit at the computer, waiting for customers to ask questions, then it's probably time to outsource your customer service to a person or company that specializes in chatting with website visitors. Remember that if you decide to use a person or company that isn't in your timezone, that you'll have to make some decisions on when you'll need them to be available for chat.
Do you have a customer service manual in place?
Whether it's you manning the helm, or someone else, do you have specific policies in place for someone to refer to when they have a question? Make sure to create a guide that answers frequently asked questions, establishes policies for when/if they should contact you, and give them a little bit of wiggle room to make their own decisions. Tim Ferriss describes doing this in his book The 4 Hour Work Week where he allowed his customer service staff to make their own judgement calls anywhere up to $100, which gave his staff a sense of ownership and drastically cut down their need to bother him with questions.
What's your budget for software?
Luckily, chat apps run the gamut in terms of features and prices. When researching this idea, I stumbled on a site which offers a guide to the best live chat software, both paid and free, so that would be a good place to get started if you're totally green.
Do your customers even want this?
Lastly, and most importantly, is this a feature your customers are asking for? If you're not getting multiple hits to your site every day, then you'll be wasting time and money. If you have a good number of visitors each day, though, ask your customers via a mailing list or social media how they feel your website handles their questions or concerns. Do they often feel like they have additional questions? Is it hard to find a way to contact you? Make sure investing in additional features on your website will be a benefit to your customers before you begin.
If you cover all of these bases ahead of time, then expanding your customer service capabilities should be a no brainer. But do your research and make sure that the investment in time and capital will be of value to your customers in the long run.