Earlier today I installed the winter tires (mounted on alloys) on a friend's 2012 Mercedes C300. It was interesting to see that this car uses bolts into threaded holes in the hubs to hold the wheels on, rather than the much more common studs and lug nuts. I saw this on a few Mazdas back in the '70s, but had not seen it since. It makes installing the wheels a bit of a challenge.

Is this standard for Mercedes? Any other manufacturers? What are the advantages?

VW's used wheel bolts instead of studs.

It's standard for most of the German makes, AFAIK.

A co-worker has a '17 VW Tiguan and it uses bolts too. It sucks compared to studs. At least with studs you can kinda hook/hang the wheel while lining things up.

Yes on it being a German thing. Both cars in my signature use wheel bolts. Mercedes Sprinter vans also use wheel bolts.

Using lug bolts also gives you more variation in terms of the wheels and offsets you can use. You can use longer bolts and spacers for different wheel offsets.

BMW has had it since the 80s, All european cars have had it since I started working on cars in 2001.

My wife's 2014 Jeep Cherokee had the same set up. Yes it's a little bit of a PITA to put the wheel back on.
I don't know yet about her 2016 Grand Cherokee as I haven't pulled a wheel yet.

In the tool kit on most German cars is supposed to the a threaded "Wheel Hanger", check you owners manual. Some are plastic and others steel. If you know the metric thread size you can order one from Amazon for about $10. Available in 12x1.5 14x1.25 etc. Makes the job much easier.

Steel wheel hanger $10

Like QP said. Every German car I've owned had lug bolts rather than studs and nuts.
Every car also had some sort of helper included in the original tool kit from which you could hang the wheel while threading in a couple of the bolts.
Not sure why this particular design was used, but I'm sure that Trav will be along to give us the reason.

Just use a hanging stud, you can but one or just cut a bolt, its a non issue. One advantage is you don't need to remove the caliper bracket to swap the rotor just remove one caliper pin bolt and flip it up.
Another reason is in Europe most drivers have aluminum wheels for the summer and steel for the winter, they use different length bolts.

https://www.amazon.com/Steel-Wheel-Hanger-Automotive-Volkswagen/dp/B00MWAQGSQ

My VW and Audi have them and it just takes a little getting used to. There is a dowel type thing in my tire change kit that you can stick in a hole to help line up but I've never used it. Being hub centric the wheels fit snug to the hub so I just jam it up there and spin to line up the holes. On the audi wheels there is a slight indentation on the backside that makes a slight rust mark where water gets into the indentation and makes a distinctive mark on the rotor surface where the wheel snugs up to so once I have the wheel on the hub I just spin the wheel until the rust mark lines up with the indentation and presto bolts drop right in.

The last car I had with lug bolts was my 1949 Plymouth. I've seen it more recently on light-duty trailer axles.

Thanks all for the feedback. I bet there was something there, but I didn't think to look for it. (If you don't know a thing exists, you don't look for it.)

Another interesting thing was that the car came with one anti-theft bolt per wheel (plus four normal hex-head bolts per wheel). Each anti-theft bolt had a very complex pattern (which was the same for all four anti-theft bolts), and there was a matching male key. I was worried that I wouldn't get the anti-theft bolts off, but they weren't too bad. Some of the other bolts were on way too tight; I guess having to use a key prevented the last shop from torquing the anti-theft bolt down as hard as the others.

When they corrode and rust away, what's cheaper and easier to replace: studs or bolts?

I wonder how many people remember left hand thread studs and lug nuts on one side of Chrysler and GM vehicles.