A lot of these tools actually make your life easier and faster in the long run.
ControlTower for example. Takes about 30 mins to setup on normal AWS (on GovCloud it was much more complicated, took me half a day). But then setting up new accounts is one click and it’s preconfigured with correct restrictions and security measures, which individually would take several hours per account to do without controltower. So it’s an easy savings from the beginning. The only real cost is the cost of AWS config. So if you’re using that already (for SecurityHub for example) then it’s nothing additional.
IAM Identity Center makes user management not only more secure but faster and easier. It will take half a day to maybe a full day to setup the first time. But now every new user will be a few clicks with access across multiple AWS accounts. You can remove them in one click across all accounts. So these are just really simple additions to your workflow that save you time and improve security.
SSM is another example. It’s adding a policy to your instance role and checking a box (or adding a flag in Terraform or CLI) and it’s enabled. It’s no additional cost. It saves you time because you don’t need to manage user accounts on the server anymore (they are managed broadly through IAM or PermissionSets). No more copying around SSH keys or rotating them when people leave. It improves security and saves you time.
There’s little (if any at all) downside to any of these things. It’s all upside. For the most part, these don’t even have any significant costs associated with them. They are generally provided for free where you’re only cost is the underlying resources that you’re managing, which of course your paying for regardless.