That’s not a negative- fan cooling is a bonus for longevity imho
I honestly have no idea. Morningstar uses large heat sinks and no fans. Their marketing says fans can fail, push dust into the unit. On the other hand Victron is known To be very reliable.
The only fan failure I’ve come across is a samlex unit on YouTube.
I’ve left computers on in my home for years and no fan failure. They DO collect dust.