Elise is hard, but not in a mechanical sense, but her playstyle.
She's not difficult in terms of understanding mechanics, after a game or two you pretty much understand everything her kit does and combos, but being an effective, aggressive, and early pressuring Elise takes a lot of confidence in using her properly. An Elise main will be more commited to diving towers early on either with flash cocoon combos or just going deep in but a new Elise may mess something up like cocoon a minion or never commit to dives despite having rappel.
In bronze she's very good to carry and climb out as since she can get lanes fed and snowballing so stupidly quick, and people are used to Elise players being a little skiddish and underestimating their actual damage when they commit, but its a matter of the Elise player's performance and commiting to ganks/kills even under tower.
She takes practice but she's definitly no where near
in terms of skill ceiling, possibility to screw up hard, or very difficult jungle clears that you can barely handle when new. I am a one trick, but I've seen friends climb out of bronze by just reaching level 5 on her and gank lanes early without actually dueling much theirselves.
TL;DR; Very easy to learn, a little tricky to master.