Every app you install, every company that has your personal information is a security risk and a stability risk. You simply never know when a bug or data breach is going to affect you. I understand that is an extreme way of looking at things but I feel that is where we are at these days.
Of course, an argument could be made that MacUpdater enhances security because it keeps your programs up to date. But so does leaving the program's automatic update feature enabled and that doesn't add expense or complication to your system.
It is definitely not bloatware, it is a program that tries to offer a convenient way to keep you software updated in as timely manner as possible. And while it does do that, IMHO, that benefit is so minor that it simply isn't worth spending money on (they do have a free version that you can try).
-kp