The article mentions
Clustering Integration Services is not recommended because the Integration Services service is not a clustered or cluster-aware service, and does not support failover from one cluster node to anoth
The SSIS service is just there for backwards compatibility, in other words for people still using the package deployment model.
For newer projects using the project deployment model, the service isn't used but rather the SSIS catalog (along with the SSISDB) is.
Can the catalog be clustered?