"mechanical lock vulnerabilities are preserved"

I've never been to a hotel that uses an ordinary key since those can be easily replicated, so that point is moot: all the electronic locks (most common these days) already have this "vulnerability" ("so why put a lock there in the first place?").

Second, since this system is being developed to use a smartphone, the security is easier to manage than a PIN code (such as 000000...). One can use centralised key-servers, etc.

Third, the company making these locks (the physical part) is ASSA Abloy, which is an extremely reputable lock company instead of the one in your link.