What a spreadsheet handles well
A spreadsheet is a simple way to list vendors, prices and dates. It can work for an early inventory, especially when one person maintains it and no sensitive information needs to be stored alongside the data.
Where it reaches its limit
A file does not inherently connect a subscription to workspace roles, per-subscription permissions, protected credentials or TOTP. A shared sheet can also make it difficult to answer who has used an account or to remove access when responsibilities change.
What changes in Subment
Subment provides a structured record for subscriptions and a workspace access model around them. Secrets are encrypted and masked until requested; sensitive actions are logged. You can still export subscription data, while exports intentionally leave out passwords, keys and 2FA codes.