SubChecks vs Notion
Notion can store your subscriptions as a database. SubChecks tracks them, reminds you before they charge, and does the math automatically.
You can build a subscription database in Notion. You can add columns for amount, billing cycle, and renewal date. But Notion won't send you an email when Netflix is about to renew. It won't calculate your real monthly spend across annual and monthly plans. It won't remind you that your free trial ends tomorrow. For that, you need something purpose-built.
Notion is incredibly flexible. That flexibility is also why it needs hours of setup to do what SubChecks does out of the box. If you want subscription tracking that just works, SubChecks is the faster path.