Data released over the past few weeks have painted an ugly picture of the Apple Watch’s initial months. Analysts say users are struggling to find a compelling use case for the wearable — besides those phallic doodles, of course.

The most alarming data came this week from Slice Research, which picked through consumers’ online receipts to come to the determination that there has been a 90 percent decline in sales since the watch’s opening week in April.

A number of Wall Street analysts have lowered their forecasts on Apple Watch in recent weeks, citing supply checks that indicate weaker-than-expected demand.

In a note to clients last week, Pacific Crest said demand appears to be “slowing quickly.” It reduced its unit-sales estimate for fiscal 2015 to 10.6 million watches from 11 million and lowered its fiscal 2016 estimate to 21 million from 24 million.

In May, RBC Capital Markets went so far as to say Apple had botched the launch.

The problem is that Apple didn’t launch the watch with a compelling use case, said Endeavor Research analyst Richard Windsor.

That may seem like an odd analysis to some, as users can check Instagram, unlock car doors, track the steps of their run, and send quick texts, or even their heartbeat, to friends. But that hasn’t spurred the masses to buy the device nor set the stage for long-term use, according to the estimates from individual researchers and Wall Street analysts.

“Apple’s failure to come up with a compelling use to which the device could be put is the single biggest reason it is underperforming,” Windsor said.

To be fair, the challenge of creating long-term stickiness among consumers has been a problem in the wearable-devices market for some time, including for popular fitness bands like those from Fitbit Inc.

In June 2014, a survey of 6,223 US adults conducted by Endeavour Partners found that 50 percent of users lose interest in wearables within a few months. It concluded that abandonment rates were high despite increased adoption.

“The industry continues to struggle to deliver products and services that provide sustained benefit to the mass market,” the Endeavour Partners report stated.

The wearable business was hopeful that Apple, with its demonstrated knack for swaying consumers to try new devices, would shift the data in favor of wearables once it entered the market with its smartwatch. But Apple, disappointingly, has performed in line with, rather than above, historical expectations, with sales that have dramatically decelerated after an early pop.

This brings us to the elementary-school-maturity-level pictures of male organs, which have nudged their way into the Apple Watch’s early uses case. While people are undoubtedly using the watch for the more serious matters it was intended for, such as keeping tabs on their email while on the subway, they haven’t been able to stop themselves from bragging about the doodled penises they are sending to friends.

Windsor emphasized that the hardware itself shoulders very little blame for any Apple Watch underperformance, adding that wearables in general can be expected to “massively underperform the hype” until the search for compelling long-term uses yields results.

Apple has been tight-lipped on watch sales so far. Its shares were down 1.6 percent to $123.71 in Wednesday morning trading, pushing them down 1.5 percent for the last three months, virtually in line with the decline in the broader Dow Jones Industrial Average, of which Apple shares are a component.