It makes sense to use ECDSA for leaf certificates, because the TLS server can then handle more clients compared to a RSA based certificate of the same strength (the private key operation is much cheaper with ECDSA and is needed for every TLS handshake). The client of course, needs a few more cycles to verify the signature, but that is not noticeable most of the time.
IMHO it does not really make sense to use a ECDSA root certificate unless you have a very constrained environment, where every byte counts. The root certificate will never be transferred to the client during a TLS handshake - so the size benefit is minimal (the intermediate certificate will be a bit smaller, because ECDSA signatures are smaller). But the signature validation will take more cycles on the client in every TLS handshake.
Other than that it is a good thing that Let's Encrypt now has an ECDSA root. When researchers might find a problem with RSA in the future, we have an alternative ready to use.
It makes sense to use ECDSA for leaf certificates, because the TLS server can then handle more clients compared to a RSA based certificate of the same strength (the private key operation is much cheaper with ECDSA and is needed for every TLS handshake). The client of course, needs a few more cycles to verify the signature, but that is not noticeable most of the time.
IMHO it does not really make sense to use a ECDSA root certificate unless you have a very constrained environment, where every byte counts. The root certificate will never be transferred to the client during a TLS handshake - so the size benefit is minimal (the intermediate certificate will be a bit smaller, because ECDSA signatures are smaller). But the signature validation will take more cycles on the client in every TLS handshake.
Other than that it is a good thing that Let's Encrypt now has an ECDSA root. When researchers might find a problem with RSA in the future, we have an alternative ready to use.