Being open source does not necessarily mean that you are safe, as you must ensure that the code that you install on your device is the same as the open source code and that there are enough reviews to say that this open source code is safe.
You can verify that you are installing the same code by verifying the signature, but there must be enough reviews, otherwise there is no difference between closed source and open source code.
That is also a valid concern about open-source projects. Regular users can't make a judgment on their own. They cannot understand the code. So the whole idea of open source must mean it is safe is a misconception.
The last point for the end user besides ensuring the reproducibility of the program is also the project must be massively used by the users, and that might come from consistent development with a good ecosystem. So the project gathers and attracts technical people to work toward the developments. More eyes should be able to detect in case if there is something shady or wrong within the code. So the trust within the community itself is already built.
It has both desktop and mobile compatibility, but the desktop version has more features built into it than the mobile version.
Metamask has a standalone desktop wallet software? I only know of the browser extensions and mobile apps
I'm pretty sure he means the browser extension instead of an installed desktop software.
Mycelium is open source, though its developers started using it to advertise scams, so I don't like it.
Those ads are the reason I uninstalled this wallet.
I forgot that they do advertise a scam. This should also be noted that some open-source project teams might be prone to such bad ethics.