Is it safe to drive with spare wheel but with proper tire?

I recently got a puncture and had to swap out the entire wheel. Luckily, the spare I had was a full size tyre, i.e.: not a skinny tyre like you sometimes see.

It looks roughly like this:

So, the wheel looks roughly like the one in the image but the rubber tyre itself is a full-size one that matches the rest of my tyres.

I used the same lug-nuts as before to attach the wheel. I do not know whether they are officially supported, however I didn’t have any issues during the installation.

Someone warned my that this wheel is not as thick as standard alloyed wheels and there is a risk of it wearing out near the lug-nuts.

Is it a problem to drive like this, especially at long distances and high speeds?