Linux support would be useful, but I think people underestimate how much legacy architecture BAS carries. Its foundations go back many years. Proper Linux support could require such extensive changes that it would effectively mean building a new BAS runtime.
Keeping the editor on Windows reduces the scope, but the runtime, browser integration and native dependencies still have to work reliably on Linux. Adding another compilation option means having a working, maintainable implementation behind that option.
The developer would also need a deep understanding of each supported OS: its system APIs, process management, permissions, dependency handling and debugging tools. Then every release needs testing and maintenance across those platforms. That is a substantial ongoing responsibility.
C/C++ cross-compilation adds another headache. Toolchains, native libraries, linking and binary compatibility all need attention. Getting an executable to compile is one milestone; making it run reliably on users’ servers is another.
Even the published BAS build guide still lists Qt 5.6.0 and Visual Studio 2013/2015. That does not prove current releases use those exact versions, but it hardly inspires confidence in the modernization of the underlying build stack. If keeping the existing SDKs and tooling current is already a problem, supporting additional operating systems would multiply that maintenance burden.
I would expect serious architectural modernization to come first. Otherwise, Linux support risks becoming another layer of workarounds on top of an already very old foundation.