This is pretty cool to see. Obsidian is looking for folks in the community to help build an importer so Notion users can easily switch (and hopefully sync) to Obsidian Bases.
I still have not figured out a good use case for Bases yet, as the cell options are not as robust as Notion (drop down, multiple select, check boxes, filters, graphs, etc.). I run my company off Notion, but will be switched to Google Sheets since they added a ton of new features - and it's free.
Another reason I am moving away from Notion is because when you export your data, it’s a mess. Random file names, files within files. It's just not easy to navigate. With that said, I don’t know an easier way to do it. Hopefully, something like this would help sync data easier as markdown is much more user-friendly than the random .CSV files Notion export generates. You're almost punished for adding text w/in the file instead of cells for everything.
Regardless, I think this would be awesome to see in the near future, especially if it can sync.
Update - You can filter in Obsidian.