They (Google) are probably using tools in a different way. I would imagine if you ask Bard/Gemini something, it also does a google search at the same time and provides those results as a potential context that the chat bot can use to answer with. So it does a google search every question but doesn't always use it.

With chatGPT it only uses the tools if it thinks it needs it. So if it needs to do a search it will have to respond with do a search function, which then has to go do a search and then it provides that as context to the chatbot which then can respond from that data.