Depending on which perforation gauge your stamp is, it could have a catalogue value of £19, £5.50, £60 or so uncommon that Stanley Gibbons can't quote a price for it. Unfortunately, the damage to the top left of the stamp will reduce its value considerably.
Perforations can be interesting, though. If you want to keep your collection simple, and ignore its value, you can also ignore the perforations. If you want to go a step further, and consider the small differences between stamps (that can make a big difference to their value!), you will need to pay attention to the gauge of the perforations.
And when you become highly specialised, perforations become very important.
As an example, 80 or 90 years ago, the Indian State of Cochin had its stamps printed by Perkins, Bacon in London. They were the printers of the Penny Black - the first postage stamp - and were still a big and busy printer. The big Gibbons
Commonwealth and British Empire Stamps 1840-1970 catalogue says that the 1916-30 set of Cochin, showing Raja Rama Varma II, was perforated '13½ to 14'. Most collectors will be happy to stop there. However, Gibbons mention in a footnote that in fact four different perforating machines were used. Each produced slightly different sized perforations, which you can distinguish with a good perforation gauge. Gibbons also list which machines were used to perforate which stamps, but don't give prices for them.
The 9 Pies stamp on this cover

is from a type 'b' perforating machine, which was previously not known to have been used to perforate the 9 Pies stamp. Not worth very much, perhaps, but it's nice to know that I have something noone else knew existed. And to know that I've increased our knowledge of the stamps of Cochin State ... by maybe 0.0001%

So it's all up to you. You can just enjoy your stamps and not bother with the perforations. Or you can go more deeply into your stamps, and find the small differences between them, that give more depth to stamp collecting.