Well, you DO actually need both machines to do the job right. Yes, you can probably do it pretty well with only the jointer, but it is tough, But the machine you are showing us in the photo at least is what I think to be a combination jointer/planer. I believe Sheppach is a UK brand. Such combination machines are more popular in Europe than in the USA, as often there is not as much room in the shop. I would suspect that the same thing is true in Asia. Most of the Combination tools take some set up time usually between the two modes and thus are slightly less desirable than a dedicated one purpose machine, IF you have the space and money. However there are some that are pretty quick to change back and forth. Jet makes one I believe that might well be similar to the machine you are looking at. You might look at the Jet website for their combination jointer/planer. Usually to use as a planer, one of the tables, possibly the in-feed, and the wood is fed in and references off one surface while passing under the cutter head. I don’t have any experience with such machines, but they are basically similar to the stand alone machines.
to answer your question, no, it is not exactly as you say. And while jointers are dangerous machines, and should be treated with respect, they can be used safely, when operated in a safe manner.
First, understand that you have a flat surface to feed the twisted or cupped, or bowed board in on. If you have a long board, with a lot of bow, then it is obviously nicer to have a long bed jointer, but you can also cut the board shorter, closer to the finished length of the piece you want to cut from it. Then you place the piece of wood flat on the in feed table. You feed that piece, by pushing it slowly across the cutter head. If you have a stable surface, that is, if the board doesn’t rock as you start pushing it thru, then for at least a bit, you are cutting a flat planar surface coming out on the other side of the cutter head, right? if you kept cutting with downward pressure on the in feed, eventually you would be cutting off whatever points the board is riding on and you would start getting a board that was not planar coming out of the other side. But if you instead, after feeding thru a foot or more past the cutter head, start applying more and more downward pressure on the OUT FEED table, then you are now referencing the flat, planar part of the board that has just been cut along the flat planar out feed table. Then, even though you are cutting off the points and ridges that you were originally referencing from, you still end up with a planar cut. Is this clear? I could describe the process a bit more, but maybe it is clear? That is, what I consider to be a common mistake of folks using the jointer. They think that all the pressure is on the infeed table. If you always apply all the downward force on that side, you will not get a flat planar face. But if you apply the downward pressure on the outfeed end, as soon as you get some amount on that side, you do. To that end, on my larger jointer, a 12” old Crescent, I use a stock feeder to apply the downward pressure and actually pull the board thru. This results in a great cut, as there are no stop/start marks which are common with a lot of jointer work, where the feeder is less than perfect in keeping the force downward and the forward feed consistent in pressure and speed. Obviously when you think about it, different types of problems, twist, cupping, warping and bowing all have a bit different methods of handling them. And you want to cut a board that has flat grain such that the grain is not being chipped out. All those things you learn as you cut wood. It is not hard to figure out, and actually the part of figuring out how to do some job is half the fun.