I don't understand this sentence:

My impression is that all tokens build on SE would suffer because of steady STEEM selling pressure and SMTs would be the only solution allowing tokens to be fully "disconnected" from that problem. Is that correct?

Steem Engine is already disconnected and perhaps more so, Steem Engine is a completely different side chain and even has deposit and withdrawl on/off ramps to other coins such as EOS, so Steem Engine is infact less connected to Steem as far as I understand it. SMT's will be directly on the Steem blockchain and can be listed on any exchange that lists Steem.