I have been using eOS for years without any of the Simple Mobile apps. I have checked them out on occasion and I wouldn't call them "bad" but I have always been able to find more capable open source apps that fit my needs better.
Just one example, I've used Material Files for years and it has quite a few features not found in Simple File Manager.
Just one example, I've used Material Files for years and it has quite a few features not found in Simple File Manager.