So you are assuming the hotel has no cameras

Silly, silly movie but I'll defend it
They were establishing a trail for future investigators to pick up on. Walken was seen with him but not by anyone who'd remeber their facesexcept maybe the annoyed bartender (a gaffe thanks to Watson). They have the taxi ride, the footage from the tourists. Anyone else who tries to add testimony to the story could be ignored because guess who the investigators will bemost likely the same men who set up Watson in the first place.
The taxi ride was necessary if only to help establish the official story.

This movie was just awful, all around.

Walken met with him a bunch of times, so they weren't trying to disconnect from him. I think the bigger plot hole was what governor has 3 rallies in the same morning in the same hotel? That is illogical. She also was able to go to sleep in her hotel room within her busy morning schedule? This movie was just awful, all around.

Even the taxi driver was like man cant believe he wants a ride to a place so close.
True, the taxi -driver comments about the proximity. I think the premise is that Smith wants to get the ball rolling without delay and it allows the red herring of the" help message" on the card to take place.

Even the taxi driver was like man cant believe he wants a ride to a place so close. His expression when he said Man i can see it from here was pretty funny.

Right there - that's one thing I thought was ridiculous all thru the movie. Walken is hanging all over him. He wasn't even trying to stay disconnected from him. Ugh this thing was weak.

very good response ethan. however didnt watson go back and forth to the van like 2 times. i havent seen it in a while but im certain he went back to the van to try to get his daughter but that lady had her at gunpoint right??? so if he had succeeded in the assassination they would have traced his steps back to those moments near the van.

My guess is they didn't want any connection to him. If the plan had succeeded and he ended up shooting the governor the FBI would trace back his steps, who'd he arrive with? How'd he get there? The chances were greater of them being spotted with him had he exited their vehicle and someone happened to see
They'd then be linked to the crime. A search would be put out for the van in connection to the assassination.
Letting him take a taxi gets that out of the way. That way he was just some nutcase a taxi driver picked up from the train station. All hands are clean.

A small plot hole.