I dont expect a decentralised platform to be profitable and also think donations are better than in-app purchases.
But I dont want big instances to suddenly turn off because they cant afford it anymore or the development being behind so much we loose users to missing features.
Looking at the donation pages of lemmy instances there are enough donations for now but it is good to have a plan B for in case we get flooded by users not willing to donate so this platform survives long term. That plan B should be as least Invasive as possible,so no ads,analytics or paywall. Thats why I suggested something that is completely cosmetic.