I just experienced this same frustration yesterday. Usually, I build custom themes with custom blocks, and remove any blocks not needed/supported by the theme. However, I'm supporting a client with a purchased theme who is adding additional languages to the site. They have an accordion plugin that uses shortcodes, which a pain to manage because you have multiple places to enter/change content instead of having everything in the page. I figured switching to an accordion block would be beneficial before translating the site into 6 different languages. However, the only well supported (backed by WordPress focused companies) accordion blocks I could find are bundled with other blocks. The problems with bundling blocks are: I don't have budget/time to make sure all the other blocks look nice or work well in this purchased theme, the extra blocks create confusion for site editors and don't follow the premise of "decisions, not options", and there isn't a way to easily disable blocks for every user, and never allow the bundled blocks plugins to add more blocks to the site in the future. I wish bundled blocks plugins had separate settings to exclude/include blocks (instead of the user's page preferences) where you can check which of the bundled blocks you want to enable for the theme. More like Jetpack's options instead of per user options.

And before anyone points out the allowed_block_types filter - yes that is great if you built the site and have controlled what is added to pages from the start. But, I don't know what blocks have been used throughout the site and what the site editors are used to - and the names of blocks change, gosh darn it: see core/button[s] and core-embed/[service] . I could build a custom block, but it isn't in the budget.

And sure, you shouldn't look a gift horse in the mouth, but I can't be the only one who has these frustrations with bundled block plugins.