It is proven and tested that Bitcoin is a good investment in the long-term and that cannot be denied, and Bitcoin has many features that other cryptocurrencies do not have, even if it is used as a payment option online it is a big deal how much more even with the opportunity it gives to people. In addition to this it also provides savings in the future, so the scalability that you are talking about is only a low percentage of the problem that a bitcoin holders will face honestly in my opinion.
I agree with your options and opinions, and have been trading since last year. But in the coming times when the internet advancements and the technology advancement and many other web related projects come into the market, some factors must affect on to the values of BTC like, its Scalability, Volatility and market maturity, Security and hacking risks etc and will face several challenges that may impact its future while Bitcoin has gained significant popularity and recognition. In view of the comparative assessment of the market and the prevailing conditions, BTC will face some challenges till now, and I will not hesitate to say here that there is already a very good and secure system is in Place.