Both will probably be non-existent in a few years. If by some chance Monero survives it will find its use as a privacy-centric currency / store of value, not as an investment vehicle. The non-fixed emission (to maintain mining incentives ad infinitum) means that it will never have the same scarcity as Bitcoin, but I think it's already been demonstrated that scarcity in altcoin distribution is wholly overrated.
Thanks you very much for your extensive explanation.
What do you mean with scarcity? I thought Monero has got a maximal total amout of around 22 mln coins.