This morning, activist investor Carl Icahn issued an open letter to Apple, urging the technology innovator to buyback more shares. As an industry analyst, I am more interested in Mr. Icahn’s rationales and assumptions about Apple’s future growth, and there are plenty in that open letter. We agree with Mr. Icahn on many fronts but also disagree with him on several other areas. Here is a quick summary of how I dissect his arguments.

What we agree with Mr. Icahn:

1.       Mr. Icahn correctly pointed out iPad’s potential in the enterprise market—we think that as consumer market for tablet slows, tablet as a PC replacement in the enterprise market will pick up. With matching accessories (keyboards, displays, projectors) and enterprise software, especially given that Microsoft makes Office on iPad, the replacement cycle will pick up steam in the coming years. The rumored 13-inch iPad will further this trend.

2.       I also agree with his view that the Apple Watch will be a control device for many of the smart home applications/devices. This is always of our thesis when we examine the wearable’s market, especially the smart watch. Just a time-piece or as an activity tracker will limit a smart watch’s appeal. Apple’s approach will make its Watch a dispensable part of people’s everyday life, not just glancing over time or receive Facebook messages. No company is close to Apple to have the pieces to make that kind of experience, and even Apple is still at the early stage of that vision.

3.       Lastly we agree with him that the latest iPhone 6 and 6 Plus will expand Apple’s market shares in the premium smartphone category. For the near term, Apple’s position will be strengthened and revenue potential is perhaps much higher than sell-side analysts’ projection.

Now, what we disagree with Mr. Icahn?

1.       I think Mr. Icahn perhaps underestimates the competition in the premium smartphone market. Apple may score big with its loyal user base with the new models, but he can’t just call the company’s competitors “junk.” The collective smartphone sales of these “junk” companies dominate the global smartphone market and a few models are as good as Apple’s latest innovations. Smartphone’s buyers today are much experienced and savvy, and Apple’s new models will pop up sales in a few quarters, but I assume the competition will catch up, especially in markets outside of U.S. where Apple’s fan base is not as loyal.

2.       We also think that Mr. Icahn’s assumptions about Apple Watch are aggressive. Even he and his team used conservative assumptions—20 million in 2015, which implies a 10-15% attach rates to iPhone sales, we are not aggressive as they are, especially disagree with the ramp-up speed of his team’s projection as similar to iPad. We think although Apple Watch is a top-notch product in its category, consumers will take time to appreciate its value and it will take time for Apple to line up all the goodies it promises to consumers—HealthKit, HomeKit, Apple Pay and all the applications that drive consumer interest and usage. Although we agree with Apple’s vision, execution still takes time in the healthcare industry, smart home space, and payment industry. Using a conservative attach rate to iPhone sales is a simple gloss-over of the challenges in the complicated ecosystems of these industries. User experience will be limited by what Apple can accomplish, and in these industries what Apple can do sometimes are constrained by its partners’ willingness and time-table.

3.       Mr. Icahn’s analysis on Apple Pay is a bit rosy too, especially on the assumption about 80% of merchants will adopt an NFC-enabled terminal by 2017. It is true that with Apple joining the NFC party, the device industry removed a barrier to scale regarding NFC adoption. But whether merchants are willing to invest in new terminal technologies and how fast they will replace remains a question mark. Remember that banks and credit card companies are pushing for chip-and-pin technology and merchants were slow to respond? We are not as optimistic as Mr. Icahn on merchants’ adoption of NFC-based terminals. Although we agree that Apple will be a front runner in the mobile payment industry, the fruit of that initiative may be later than what Mr. Icahn predicts. We will be watching closely how payment terminal vendors such as Verifone, reporting their business growth before we fine-tune our assumption of payment market growth.

In sum, we think that Mr. Icahn’s letter highlights a good part of Apple’s strategy that is less understood by the investor community, but his thesis still has holes, especially his growth assumptions.