Cryptocurrencies use decentralized control as opposed to centralized digital currency and central banking systems. The decentralized control of each cryptocurrency works through distributed ledger technology, typically a blockchain, that serves as a public financial transaction database.

Recently, I see a lot of information that decentralization is a trend in 2019, and you should pay attention to ICO and projects that support decentralization (mainly exchange platforms). Who knows,maybe it will be best investment.

It seems to be that way yes. I've also noticed more people starting to talk about ICOs too or maybe I just missed it. Especially the word "decentralization" I think might be a trend for 2019. DEX platforms are getting really popular today. The projects starting to use Ethereum for their tokens again which might influence on price to rise also.

I'm close to your opinion
For ICO, 2017 was good, and 2018, on the contrary -was bad, so I think that in 2019 it will be  neutral: the shitcoins will contine fall off, and there will be lot of good projects,  for example, decentralized exchanges and STO look promising.

 In general, it is difficult to predict the future especially if it is a cryptocurrency future). But we can roughly suggest what trends should be expected in this year.
2019 will belong to the security token. So far, security token offerings make up only a relatively small percentage of ICOs. But that will soon change. Security tokens, not utility coins, will attract significant amounts of Wall Street money this year
 New  Decentralized exchanges platforms will be simplified and give control back to the users. What’s more, with multiple platforms vying for success in the marketplace, it’s good news for consumers who will have more choice. Possible drawbacks include difficulty in managing high liquidity and providing customer support to such a large, sprawling platform.