A good manager will ensure everyone has actually read Filthy Rich Clients, is aware of Swing theme component libraries and never does IO on the UI thread.
And for bonus points, that the team gets hold of an Java AOT compiler to native code.
Is it really that much worse than HTML, JS, and CSS? The DOM is generally a mess and CSS isn't easy to use.
Of course JFX is probably a better option now days but for a small GUI if you avoid layout managers like GridBagLayout (built to work with a WYSIWYG) and you are on the JVM seems like an easy option to me
How do you make a good looking app with Tk? I know about Tile and Ttk, but how can I even trust those when the Windows look and feel they mention is that of Windows XP? Launched in 2001, abandoned by Microsoft in 2014 (!)
I wouldn't base any commercial product I'd make on Tk, if it was meant for a large audience. Internal tools where you get to tell you users: "shut up and use the ugly app cause management already paid for it", ok, there you can use it. Otherwise... no.
Ask people off the street instead of HN developers who like to pretend their undesigned weekend project looks good just because it almost works, and you'll find consensus more common than you think. Or even better, how unanimous the consensus is on what looks like shit.
Personally I'm a fan of C# with WPF, but while C# is decently cross-platform with .net core WPF is Windows only.