Is there value in talking to investors as a bootstrapped company?

I've been running a profitable bootstrapped B2B company for a few years now. Growth is better than ever, staff is growing, business is well. This is the first company I've ever started.

Over the last year or so, the frequency at which VCs and private equity firms (their partners as well as the typical analyst emails) reach out increased, and I'm not sure how to best handle them.

We're not looking for investment and I'm ignoring most of these emails, but every now and then an email stands out and we have a chat. I'm upfront about not looking for investment, and they're interested in "building a relationship" and "staying in touch". We chat about their investment approach, I tell them why our company is the best at what we do, we chat about the industry a bit and then part ways after 30 minutes.

I thought after a few dozen calls like this over the year I'd start to see something I can get out of them. But I don't even know where to start.

So I need advice. Is building relationships meaningful at this stage to have a leg up if we decide to raise funding in 2-3 years? Is there more I can get out of these calls? How are other founders who aren't fundraising handling this?

Thanks!