Why win and not draw?

Why did I win in this game?

en.lichess.org/uqYaKxIdykNP

My opponent timed out, but the material I had (King + bishop) was not sufficient for mate. Shouldn't that have counted as a draw?

Because white ran out of time and you still had time on your clock

You still can checkmate with a single bishop.

@Chesstroll_Berserk @moo @OceanicHarvest @pmsim
see this topic en.lichess.org/forum/general-chess-discussion/unfair-decision?page=1

You can checkmate with the single bishop. you have to trap the white king in between his own pieces and then give a check with the bishop.

Insufficient material only counts when one side has a bishop and the other side does not have any pieces

Check this out:
en.lichess.org/analysis/8/6NP/6BK/8/7k/4b3/8/8_w_-_-

Many thanks to everyone who provided an explanation.