If we limit the discussion to the effect on the bitcoin:
A problem with Visa cards does not necessarily mean that people will stop using it or resort to alternatives such as Bitcoin "It's a technical problem as long as the money is safe, trust is there."
Perhaps the effect is indirect: Increase awareness of the use of blockchain in making payments, encouraging the financial system to accept Blockchain, increase confidence in bitcoin, and accept it seriously.
Unfortunately, there might be another indirect effect.
Less knowledgeable people will turn away from any type digital payments and cling to cash, and usually, with those, it's pretty hard to explain things, all they say it "Look what happened!!!!".
And let's say for the sake of the discussion that the angry customers will switch to bitcoin...
Not all, not half of them but about 1 million, what will happen to the bitcoin network? December -February again, fees of 20$ and confirmation when god knows.
Unfortunately, without LN right now Bitcoin can't claim to be a reliable alternative for VISA.
Not for millions of users worldwide.