It looks like [0] access to gemini will only be for subscribers, given that it costs them money. This is, "of course", distinct from ai mode [1] in google search that happens from the address bar in chrome. The first video implies that the difference involves throwing the current web page into the query as context so someone can ask "is this recipe gluten-free?" on a recipe webpage.

[0] https://blog.google/products/gemini/gemini-app-updates-io-20...

[1] https://blog.google/products/search/google-search-ai-mode-up...