After building about a dozen internal tools over the past few years, I've landed on a rule that's saved us from giving away work for free.
If the tool helps someone understand their problem — it's a lead magnet.
If the tool helps someone understand AND fix their problem — it's charity.
The line is diagnosis vs. treatment. A website health checker that shows your score? Lead magnet. One that also rewrites your meta descriptions? You just did the job for free.
We built our digital maturity assessment to stop exactly at the point where the user thinks "I need help with this." Not before that point, and definitely not after it.