Full disclosure: I'm a Software Engineer at Red Hat.
Tower has a lot of great features but I hate to concede that it does come with some of the drawbacks you mentioned. I think it comes down to weighing the pros and cons, making sure you are aware of the cons and putting measures in place to avoid problems.
It also heavily depends on your use case, Tower provides things like RBAC/ACL, auditing, scheduling, online editing and execution, an API, etc. If you happen to need none of that and you're perfectly happy with just using Ansible from your command line, there's probably little incentive for you to use it.
If all you need is reporting, ARA is simple, easy to install and setup, doesn't get in your way and just records things transparently.
I figured I might as well take the opportunity of posting to leave a video demo [1], even if a little outdated, as well as an example of live report that ara provides [2].
Let me know if you have any questions !
[1]: https://www.youtube.com/watch?v=k3i8VPCanGo [2]: http://logs.openstack.org/21/474721/7/check/gate-openstack-a...