Will you still log in three months from now?
If so, use a forwarding alias or regular email. If not, and the task is low risk, a disposable email is a better fit.
Could losing the account cause financial or identity harm?
If so, do not use a short-lived address. Bank, healthcare, government, work, and primary paid-service accounts should be linked to a stable email address.
Do you need to receive attachments, contracts, or receipts?
Files you need to keep long term belong in a controllable inbox and should be archived promptly. A temporary inbox is not a file repository.
Are you only worried about marketing emails?
If the relationship is ongoing but you do not want to share your primary email, a dedicated forwarding alias is usually a better balance than a one-time address.