If you were a competitive runner then you'd probably want to cycle it so that you get the strength training benefit but also optimize for your races.
I take it. I did a 10k race and stopped for two weeks. I'm also not super consistent but I try to take about 5-10g a day.
In terms of optimizing overall health I would say take it + running + strength training is a good combination. The effects are not huge and vary person to person.
In short: seems to help with high intensity exercises and post-exercise recovery, helps with muscle development, and a bunch of other benefits.
I take 10g creatine, it did wonders for me. More energy and mental sharpness.
Strength training is essential for runners to avoid injury at high mileage. Sleep, strength, and nutrition. It can’t be ignored or you will get injured.
Some folks mention cutting it out to lose weight but at higher mileage I find it hard to keep on weight anyway.
If you intend to have any benefits of going to the gym then protein (and overall calorie consumption) would have to be monitored.
Running sort of conflicts with working out: it wants you to be light and burns plenty of energy.
Gym wants you to gain mass. No mass gains -> gym us useless.
Creatine is kind of an afterthought in this bigger picture. Might give you an extra rep or two but that's it.
Strength training isn't all about mass. You can get stronger without gaining mass. There is a neural component and an efficiency component. At some point though you do need a bigger muscle to be stronger. There is also the question of whether you're optimizing for faster (fast twitch) or slower movements.
It's not like one can move from squating 100kg to squating 150kg without extra 2-3 kgs of meat.
And there is NO WAY of growing meat in a calorie deficit. And running often leads to that.