Is this laptop worth it for gaming?

No laptop is worth it for gaming unless it is used. Then, you might be able to get a good deal. But, if you want something that is worth to game on, then build yourself a gaming rig. Although, those components in the laptop are good to game on but it isn't worth it. The processor itself costs around $200 - $250 and the gpu costs around $100 to $150 and add in some cheap motherboard, ram, hard drive, screen, and all to together would most likely come out to around $500 and possibly $600. Laptops themselves usually aren't worth it especially gaming laptops.

Walmart has a mistake. It should be gtx 1050 ti 4gb gddr5 according to the Lenovo model number
http://psref.lenovo.com/Detail/Lenovo_Laptops/Lenovo_Legion_Y520_15?M=80WK00T3US

Gaming is rank #57
https://www.notebookcheck.net/...849.0.html
Walmart shows $899 for i7-7700HQ, GTX 1050 TI 4GB, 16GB RAM, 1TB HDD +128GB SSD, 1920x1080 display

Lenovo.com shows 10-12 Business days for $800
i7-7700HQ, GTX 1050 TI 4GB, 16GB RAM, 2TB, 1920x1080 display
I do not know about adding an M2 SSD, but it would be a better value if you can, and then clone the HDD to SSD.

Sale ends in less than 1 HOUR, for $799 and tax only to NY/NJ
i7-7700HQ, GTX 1050 TI 4GB, 8GB RAM (instead of 16), 1TB HDD +128GB SSD, 1920x1080 display
https://www.bhphotovideo.com/...ku=1328142

$850 for HP Omen with 8GB RAM
https://www.bestbuy.com/...Id=6123334

The laptop at Walmart is in price range if you want 16GB instead of 8GB system ram
8GB is normally $80 to $100
add- tower pcs are cheaper.
$800 for GTX 1060 3GB Ryzen 7 8GB RAM, 1TB no ssd
https://www.newegg.com/...6883230292
or here:
https://www.bestbuy.com/...Id=6128510