That's what they're saying, though. It's better than nothing. Until rapid testing is available, that's the best option there is.
Temperature checks are part of the entire response. Even when you have widely available rapid testing, you still won't be testing everyone. You will also have antibody testing. Contact tracing. Greater use of disinfectants.
Those who are looking for a single magic silver bullet that reduces transmission to risk to 0..... That won't happen.
Instead, there will be a multi-faceted approach, that work together to greatly reduce transmission.
In epidemiology, there is a focus on the R0.... the re-transmission rate. It is is over 1.0, then there is infection growth and you have a developing pandemic. If it's over 0 but under 1, then the infection is slowly disappearing. SOME people will still get sick, but fewer and fewer.
So the goal is to combine tactics to get the R0 below 1.0.. as far below as possible.
As to the "R0" on the micro level, at Disney World specifically... the only way to keep it at 0 is to keep the parks closed. If the park opens in the next 6 months, the R0 will be higher than 0... the question is how much higher.
If temperature checks bring the R0 down from 0.9 to 0.8, then temperature checks should be a critical part of the arsenal. (And the parks should NOT open if the R0 would be over 1.0).