my advice to students is usually something like: the trend is short, your life is long. research what you are interested in, and make sure you can explain why you are doing it to other researchers (and to beancounters when necessary).

this is especially important for phd students: if you do a "trend project" for your phd, it will be both out of date and "cringe" by the time you hit the job market.

i often think about how there was a whole generation of "PL for blockchain" phds and i can only guess this was the result of poor advising...

some of those students did go on to be very successful, actually, to be fair. but five years is a long time to spend thinking about the blockchain, and I mourn for what they might have done in that time with better advice.