I’ve always had issues when people are using hours instead of points. The one time we properly used points on a team it went really well.
This is really easy to practise and test too, since all you need are a bunch of questions where the answer is known, but you are uncertain of it. Then you can guess a range in which you are 90 % certain the true answer lies, and after 10 such questions, you should be correct roughly 9 times.
Points are a way to do this, but I prefer engineers who are calibrated. It's very powerful to ask someone for a calendar day when something will be done (or really just about any other question about anything), and be able to be reasonably confident in the span they respond with.
As a concrete example, I recently estimated "somewhere between 1 week and 4 months" when asked about an semi-well specified feature because I felt there's a 5 % chance it's done in less than a week, but even under pessimistic assumptions, there's about a 5 % risk it takes longer than 4 months.
When asked about a larger, unspecified projects a few years ago, I didn't hesitate to respond "between three months and 15 years". Sometimes that's the best you can do due to the uncertainties involved. It sounds useless, but it's really useful to have a quantitative measure of the uncertainty.