Is Blockchain technology becoming obsolete?

[parishy]

There are emerging cryptocoins which don't rely on the 'old' blockchain technology. The most known of them are IOTA and NANO (raiblocks). 
I have never used these coins so far, but their developers state these coins can provide a lot of improvements and better features than traditional blockchain-based cryptocoins like Bitcoin. For example, faster and cheaper transactions, less energy consumption and so on. So do you think blockchain-based cryptocoins are doomed and the future will be favorable to these emerging technologies?

[ambar33n]

I don't think that those technologies provide the security of PoW algorithms and if you are going to use that cryptocurrency as a global currency then high level of security is very reasonable.

There is also a networking effect going on here, where bitcoins are being accepted more and more which makes them even more useful and drives even bigger adoption. I don't think that improvements of these new technologies are definitive enough nor big enough to overthrow Bitcoin from the top.

I think it is a lot risker to invest in altcoins than in Bitcoin currently.