I think online ticketing systems are fine, and yeah they mostly require to run on a robust infrastructure. Knowing the trends, that certainly would depend on big-tech cloud infrastructure.

I don't care unless this become a mandatory de-facto standard to access public places.

Hopefully yet it is not, and people would reject that if that would become an obligation. But there's a chance that our children would not even know this is bare dumb cause it would be the norm.