The question remains: What's in it for them?
They're so kind to give us this amazing free app with no ads, while not collecting anything from us. This altruistic Chinese development shop, despite having no discernible revenue stream, is so professional with their constant updates (weren't they the first file manager to implement Holo design?), and with their extremely proficient English.
Why would they want to store the Dropbox credentials that they get from us, which would open the door to even more passwords stored there by password managers for password sync'ing? Why would they collect my local PC credentials? Luckily, this altruistic company ES Strongs throws away the data, and is not pressured to give it to the Chinese government, which could accumulate it to have the capability to launch a major cyber attack.
Meanwhile, I''ll be trying other well-rated file managers, like
X-plore (has ads), and
Solid Explorer ($2 after a 14-day trial).