It is perfectly OK to only code at work, you can have a life too

Contains predictable reddit comments of never working a millisecond of unpaid time.

That’s certainly a choice; there’s nothing wrong with it.

OTOH, if you enjoy coding (as I do), there’s also nothing wrong with coding at home or doing the occasional extra work from home (and conversely, dicking off in the office now and then when there’s an opportunity).

Many find that being flexible like this yields a better outcome for all parties.

Absolutely. Aside from quite a bit of work travel which inevitably blurs the boundaries between personal time and work time (as does the fact that otherwise I mostly work from home), I generally keep work to work hours.

However, as you suggest, I also generally will do a bit of work here and there if something comes up and tend to checkin on email now and then at home. Conversely, I'll run out and do a few errands on weekdays if I need to pickup groceries, etc. I know a lot of people have trouble setting boundaries for various reasons (with faults on both employer and employee sides) but overall I find flexibility can be a better deal for everyone.

I don't get this. It is like being an accomplished painter, but never painting anything for yourself. Or a carpenter, and not making your own table or chairs.

As a coder, you have the ability to create almost anything. How can that knowledge not tempt you to create something yourself?

I'm not sure I would take "only" in that case too literally. There are a lot of people who genuinely do enjoy programming but get quite enough of it at work, thank you very much. In my case I do a lot of writing (words) for work and like doing it--among other things that are part of my job. That doesn't mean I spend every night working on writing the great American novel--though I do know writers at work who also do that sort of thing.

(I actually do some unrelated personal writing but not a huge amount.)

There are also people for whom coding really is just a job. It puts food on the table. They enjoy/tolerate it well enough for what it pays. But it's not something they want to do as a hobby.

ADDED: People can do whatever they want in their spare time. But, not to pick on you, the belief in many corners of tech that writing software must be some all-consuming passion is unhealthy.

A lot of times people have invention assignment agreements which make it really hard to have their own independent projects.