Entropy is free.

Randomly generating your own public/private keypair is not hard; but is the most important part. Learning how to build and use a device like a seedsigner in an air gapped way is much better than trusting your entropy and seed storage to a prefab device, especially if that hardware physically connects to your computer or touches the internet in any way whatsoever.

Not to mention they have additional software running on their hardware for crypto coins increasing their attack vector.

Best thing to do; is keep a cold key as cold as possible from start to finish.