Security key at the front door, yes or no?

Hehe. No, I mean I usually have at most 50 EUR cash in the apartment,

They don’t know that.

I might have about 200 on me sometimes, but that’s rather the exception. Expensive watches, expensive jewelry, and expensive ladies' handbags are not my thing (and neither is it my fiancée’s). Or rather, the rings are simply worn.

Then you’re good robbery targets

If I were to indulge in the thought experiment, I would only break into villa areas accordingly

Much too complicated. And then everything in the safe or something... the real treasures are at the bank or under your butt... Nah, it's not worth the effort.

They don't know that.

That is correct, but my question is based on whether it is worth installing a security locking system costing several thousand euros if it has to be newly purchased after a break-in when I only have a few hundred euros worth of portable valuables in the house. So whoever wants to get in will get in, then sees, if in doubt, that I have nothing anyway and then leaves again. Buy a lock for 50 euros, done.

The unpleasant feeling that a stranger with bad intentions was in my home is actually the thing I see as a valid argument for an investment. The feeling of security of one’s own privacy is priceless. But if the burglars get in anyway, it’s no longer there, and it’s not restored with the new expensive lock any more than with the new cheap one.

Then you are good robbery victims

That’s more like it, but then no security lock at home helps if I get robbed on the go.
And if I get robbed at home, probably not either, because the door will likely be open if the robber pretends to be a DHL or Hermes parcel courier.

In principle, your question is already answered on the first few pages

You mean, "do whatever you want," everything is fine as long as you can live with the consequences? Yes, but I do like to discuss.

Thieves look for side entrances, where they are not seen. You don’t need much thought for the front door, nor much money. (Slightly better) standard is okay. Make sure everything always looks lived in. Invest rather in good patio doors and windows. What was your question? #4 is also helpful!

Yes, my question was basically whether it is worth spending a lot of money on security if you don’t actually intend to keep valuable items in the house. So #4 sums it up quite well. Or always keep the TV loud. Hehe.