Almost 5 years have passed since  I got into BC technologý and its still the same issue:  its overvalued in their expectatives. Lots of money in ideas and projects that cant be implemented. SC cant work outside the BC and of course cant interact with the physical world.

Blockchains need realiable interfaces  and thats a major weakness-

Cada vez aque un programa o contrato o usuario hace algo, todos los nodos de la red deben acordar que la acción ha tenido lugar y para ello deben hacer funcionar el mismo contrato. He aquí una restricción de escala, ya que obviamente esto no es sostenible: no puedes tener miles de millones de nodos ejecutando los mismos contratos para validarlos. Para ello lo interesante sería hacer un MUESTREO de nodos a los que les toca validar, y recibir una recompensa por ello. Si la red y el muestreo se hace correctamente no hay forma de manipular esto. Para ello necesitas fuentes de aleatoriedad muy muy potentes.

Al estar los nodos distribuidos por todo el mundo, las BC tienen una elevada latencia (tiempo que le lleva a los datos moverse por la red). ETH es en realidad un ordenador muy lento y por ello de momento apenas hace unas pocas decenas de transaciones por minuto.

TERMS
Oportunistic Caching. Un sistema para crear más copias de dato populares cerca de donde son reclamados para obtener una mayor velocidad de respuesta eg en webs.

Uno de los problemas de las cadenas de bloques es que los desarrolladores que están detrás no tienen ni idea de los principios matemáticos que están detrás.


Blockchain is innovation at the data layer only
Blockchain does not bring new customer value to the user experience or the physical device (laptop or mobile phone). Blockchain applications are built with a proprietary web application that interacts with the blockchain for censorship-proof, easily audited data storage.

Very few people can explain the uniqueness of blockchain technology.


SPEED
BC is instant in itself, real issue is the relationship with legacy systems which are not. Mining uses to use hash functions 256bites. 1B transactions / second. Verification processes external can be real hard. Need some adaptation between both systems. 

FINANCIAL REGULATION
Authorities may want to slow down the processes to get real track of them, offshoring some of the benefits of the system. 

ENERGY CONSUMPTION
This is an important factor: energy consumption and heat dissipation. Servers will need to be renewed worldwide. Its a general problem for all IT systems. 

VOLATILE TRANSACTION COSTS
We need to participate with equal terms. Mining fees are a variable of the system to keep it running and its too volatile because of the BTC pricing fluctuating. 

CYBER SECURITY SYSTEMS

IMPLEMENTATION COSTS


How can anyone build a successful business in a platform that has the uncertainty of the cost per transaction and where also as the platform gets popular the business might not be viable? This platforms should get cheaper and faster as they grow, not slower and more expensive. We need the paradigms of decentralization and privacy but we also need predictability in operating costs in order to run real business in them.

Blockchain is an experimental technology: there´s no successful implementations out of BTC. Its hard to find real business cases, and in most of the proposed applications there are already centralized techologies solving them. That´s because BC is a technology in search for problems. Despite all of it Blockchains may be the heart of the 4th Industrial Revolution.

ENERGY CONSUMPTION. Blockchain is inefficient tech by design, as we create trust by building a system based on distrust. Bitcoin transactions are thousands of times less efficient than credit card transactions, by design. In the brave new world of Bitcoin, it seems that unless drastic changes are made, the cryptocurrency will continue to consume enormous amounts of energy.