I'm a Java fan so I'm contractually required to dis c#, but actually I kinda like this. It reduces boilerplate. Yes, it could be abused but this is what code review is for.
I struggle to even see how anyone would prefer that over an explicit if before assigning.
Having that on the right side (attribute reference) is great, but that was already available as far as I understood the post...
So as a casual observer, I'd say it brings more consistency.
But also as a casual observer, my opinion is low-value.
Maybe my feeling is just rooted in the fact I've never used a language which allowed ?. on assignment
Most companies don't care about this kind of stuff.
I work across Java, C#, JS/TS, C++, SQL, and whatever else might be needed, even stuff like Go and C, that I routinely criticise, because there is my opinion, and then there is the job market, and I rather pay my bills.
It was a joke.