Is there any value in having onboarding email flows for early stage companies?

The benefits you stated can all be achieved with a good onboarding flow, no question. However, whether you should be focussing on the onboarding stage right now is a question of priorities.

First of all, it's rare that implementing even the most complex, segmented onboarding emails will result in a significant step in user > activated rate. You will probably make improvements, even if it's just by reminding people they need to complete their signup, but as a startup, you need to ask yourself if those improvements justify the effort involved?

That being said, one thing that will always pay dividends is making sure you're collecting the right data, so that when you're at the scale that single-digit improvements in conversation rates make a huge impact on your revenues, then you have everything in place.

I'd recommend Mixpanel to analyse the scale of the issue/opportunity, Segment to manage the data and Autopilot to send the emails (I go into more details here - https://www.wunderkindagency.com/post/saas-martech-stack)

Otherwise, this is definitely my area and whilst things are quiet due to Covid, I'm always happy to help out founders.

Also there's 100% value to be had in improving your onboarding - I've had clients go from 20% - 30% signup to monetised (redesigned onboarding and added marketing automation) and 15% - 27% new user > activated by redesigning their onboarding.

Just don't be fooled into thinking a 3 part series in Mailchimp will make a tangible impact.

Something that I'm not seeing in the comments so far is about improving future conversion rates and flow.

For example, I send out an email on sign up that is about onboarding and development a relationship, but is also just about better understanding what got them to sign up and thus increasing my understanding of the customer and how to convert future customers.

By asking, "What compelled you to sign up?", you'll get some really great answers to optimize your landing pages. Because people will tell you, I saw this and this and that's what made me actually do it. Tie those all together and you can better understand your customers, and make your conversion rate better!

One key thing to keep in mind is that the product experience (including in-app onboarding) should be your main priority. All supplemental elements like email, push, extra incentives, customer support etc. are secondary.

Once you have that part covered, you can start with email onboarding with relatively low effort and cost. I don't know your email list size but even the free MailChimp plan has automation included. If your list is larger, you may want to try SendFox, which has a lifetime AppSumo deal at $49.

We are exploring this same question right now. We know that there is value to building out such a flow, but it's getting mixed up among many competing priorities. I'll be standing by to see what others say.

That said, I can give you a recommendation on tools. I know it's expensive and is well known, but Intercom is an absolutely fantastic tool if you have any sort of usage collection. We have a pipeline that uses Segment to send all event data to Intercom, down to individual actions on a page. We can then target users who have both signed up at a specific time and have completed a certain sort of action. This sort of granularity gives us a lot of power to be able to target an onboarding flow based upon what steps a user has taken and provide them with the right information at the right time.

Now we just have to build it out :)