Then, why don't people watch it more than Halo's? That said, it has nothing to do with it being a bigger hit or not.

Womanizer.

Halo from the Pussycat Dolls wasn't as big

Halo.

Chart (2008) Peak
position
Australia (ARIA)[79] 5
Austria (Ö3 Austria Top 40)[80] 4
Belgium (Ultratop 50 Flanders)[81] 1
Belgium (Ultratop 50 Wallonia)[82] 2
Canada (Canadian Hot 100)[83] 1
Czech Republic (Rádio Top 100)[84] 6
Denmark (Tracklisten)[85] 1
Europe (European Hot 100 Singles)[86] 1
Finland (Suomen virallinen lista)[87] 1
France (SNEP)[88] 1
France (SNEP) Download Chart[89] 1
Germany (Media Control Charts)[90] 4
Hungary (Rádiós Top 40)[91] 2
Ireland (IRMA)[92] 2
Israel (Media Forest)[93] 1
Italy (FIMI)[94] 7
Japan (Japan Hot 100)[95] 7
Netherlands (Single Top 100)[96] 8
New Zealand (Recorded Music NZ)[97] 9
Norway (VG-lista)[98] 1
Spain (PROMUSICAE)[99] 8
Sweden (Sverigetopplistan)[100] 1
Switzerland (Schweizer Hitparade)[101] 2
UK Singles (Official Charts Company)[102] 3
US Billboard Hot 100[103] 1
US Hot Dance Club Songs (Billboard)[104] 9
US Pop Songs (Billboard)[105] 1

Weekly charts
Chart (2009) Peak
position
Australian Singles Chart[155] 3
Austrian Singles Chart[155] 6
Belgian Singles Chart (Flanders)[155] 18
Belgian Singles Chart (Wallonia)[155] 15
Brazilian Hot 100 Airplay[156] 1
Brazilian Pop Songs[156] 1
Bulgarian Airplay Chart[157] 5
Canadian Hot 100[71][158] 3
Czech Republic Airplay Chart[159] 2
Danish Singles Chart[155] 15
Dutch Top 40[160] 9
Eurochart Hot 100 Singles[158] 4
French Digital Singles Chart[161] 9
German Singles Chart[162] 5
Greek Singles Chart[163] 2
Hungarian Airplay Chart[164] 17
Irish Singles Chart[85] 4
Israeli Airplay Chart[165] 6
Italian Singles Chart[155] 5
Norwegian Singles Chart[155] 1
New Zealand Singles Chart[155] 2
Slovakian Airplay Chart[166] 1
South Korea International Singles[167] 6
Spanish Singles Chart[155] 5
Swedish Singles Chart[155] 8
Swiss Singles Chart[155] 4
UK Singles Chart[81] 4
US Billboard Hot 100[71][158] 5
US Hot Dance Club Songs[71][168] 1
US Hot R&B/Hip-Hop Songs[71][158] 16
US Pop Songs[71][158] 2
US Adult Contemporary[169] 27
US Rhythmic Top 40 (Billboard)[170] 8

I think its obvious

Why is this still a question?
Halo ~9M
Womanizer ~7M

It's 7 more than Womanizer though.

Halo.

Halo and it was also more critically acclaimed.

Clearly Beyoncé's 4th single from I Am... Sasha Fierce as opposed to Britney's lead single form that album she released during the same time.

Both are completely forgotten and without South Korean 1 cent downloads and ringtone sales added in Halo has probably only sold like 5-6 million. But it was still bigger than Womanizer I guess!