Benjaminas are not the greatest "strangler" amongst Ficus trees, but they will still do it. High humidity encourages it. I have a large benjamina that has strangled 2 nearby trees. Some branches would have been against those trees and aerial roots grew down them. Now those trees are shrouded/"mummified" by ficus roots.

So, should your tree get larger, and should you leave it near another tree .........

It's already showing early signs of it's evil nature, LOL.

Are you growing in hydroculture? (That looks like hydroton in your pic) I suspect that the moist clay pellets are adding humidity to the air and that might be encouraging aerial roots to form.

Yes, it is in semi-hydro. The plant was in a clear plastic bag to save it from the shock of losing the soil. Now that I took it out, should I expect losing these roots or there is a chance to keep them alive? The air in my room is very dry.

Can one ficus strangle the other ficus sharing the same pot? Maybe I shouldn't let them kill each other :)

Yeah they will shrivel to nothing in dry air when they are all white and fuzzy. If you want to keep them,I'd advise cutting a drinking straw to lengths suitable to guide the the roots into the hydroton. Once they get down in there they should start hardening off and looking more woody before too long. Previous to slipping the cut straw pieces in place,I would also advise cutting a slice all the way from top to bottom of each one. This will make it possible to remove them later.

Also the ficus needs to be back in the bag to provide the necessary humidity to continue aerial growth for now.

Hope that made sense! lol

Ficus won't strangle another ficus, not of the same species. The aerial roots get larger and then "fuse" together, more or less becoming one tree with multiple trunks. I haven't seen 2 different species do it but would guess they wouldn't be compatable. The aerial roots on yours are close to the bottom. If you could enclose the lot in a plastic bag again that should maintain humidity enough for them to reach into the "soil".