I've been a premium subscriber for a while, even when the benefits were marginal to me, and I like Windy a lot. But, watch your premium segmentation with care, ventusky.com is free and addresses a number of models without ads [it appears to be something of a side project?].
Once people are more alert about it, segmenting certain features into Premium may be a bit pushing on a string. For what it's worth, the availability of hourly forecasting data with HRRR/NBM is why I suggest it to people not invested enough to pay for Windy to use Ventusky.
So here's what keeps me paying for Windy without complaint:
Higher resolution ECMWF
The denser presentation of forecast data across hours and days
More obscure map layers, like soil moisture
Ventusky could fix #2, in many ways the mobile application and web site are a bit more polished than Windy, but perhaps some of the polish makes it difficult to make dense and functional presentation.
They have a number of layers, so I think they could fix #3 in all practical respects for widening use cases in time.
But with their side-project-ish (non) revenue, it seems unlikely they could approach #1, assuming high resolution ECMWF costs a decent amount of money.
While I don't mean to suggest that Windy should be looking to "compete" with Ventusky for market share or anything like that, the choice of what to put behind premium and advertise as reasons to buy premium exists in equilibrium with other things available, and I guess I'm affectionate enough about Windy that I wanted to give my impression of reasons why I feel satisfied in continuing to pay for Premium, as I have for some time. Consider it a bit of unsolicited user or market research.