what are the technological limits of a smart contract?

Question

I know that:

• a smart contract cannot initiate any type of transaction but needs an external trigger. Each transaction is triggered by an EOA
• Smart contracts cannot subscribe to events or access them directly

but are there other limits?

Answer 1

"Technological limits" is a quite broad term, but some other relevant limits are, for example:

• Maximum contract size of 24 kB (see in this article)
• Limited stack depth of 1024 (see deprecated Call Depth Attack)
• And most importantly, every computation requires gas, which is limited by your gas limit (see gas costs for EVM instructions)

For a more detailed analysis of the performance of Smart Contracts, I can recommend you this paper by Di Angelo and Salzer.