Larger upside potential, while I see very little upside on BTC (personal opinion).
Nowhere near that of Steem at the moment. If BTC goes 10x it has gone 3x over its ATH. For Steem, it is 20% of the ATH. Bu.... I am biased :)
STEEM gives me MUCH MORE OPTIONS (power up, create income in voting, delegate, support causes), while as BTC is just another token. STEEM tokens can MEAN so much more than just a statement of value.
This is what I see as the future of crypto, the actions that they can be used for to make life more interesting. Cold wallet storage isn't interesting.