What is the difference between encoding a full URL like removed link with the URI identifier code 0x00 instead of just the domain with identifier code 0x02 ? Is one faster than the other in terms of reading ?
Encoding URL well known type
They are both acceptable ways of encoding a URL onto an NFC Tag. Both are NFC Forum compliant. Additionally, there's no performance different between the two.
For the benefit of other readers, encoding with the URI identifier of 0x00 would mean encoding the full URL such as https://www.seritag.com . Encoding with the identifier 0x02 means that the URL is identified as 'https://www.' and the only data encoded is seritag.com. A reader, such as a mobile phone, reading the first tag will simply take the whole URL. For the 0x02 option, the reader will add the https://www. back onto the data to recreate the full URL.
The only real benefit is that it does enable you to store more data on the tag. By encoding the https://www. you are storing an additional 12 bytes which, by using 0x02, you can avoid. On a larger memory chip like the NTAG213 this isn't likely to be an issue. On the cost effective NTAG210 chips with less memory, it might make the difference.
Seritag will almost always encode using the correct identifier. This is because it's in the NFC Forum specifications and therefore, arguably, the 'correct' way to do things. However, if you decide to encode with the full URL, it will work just as well.